FORM 6-K

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549


                        Report of Foreign Private Issuer


                        Pursuant to Rule 13a-16 or 15d-16
                     of the Securities Exchange Act of 1934


                               17 November 2004


                                    mmO2 plc


                                Wellington Street
                       Slough, Berkshire SL1 1YP, England

                    (Address of principal executive offices)


Indicate by check mark whether the registrant files or will file annual reports
under cover Form 20-F or Form 40-F

                         Form 20-F..X... Form 40-F.....


Indicate by check mark whether the registrant by furnishing the information
contained in this Form is also thereby furnishing the information to the
Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934.

                               Yes ..... No ..X...


If "Yes" is marked, indicate below the file number assigned to the registrant
in connection with Rule 12g3-2(b): 82 ________


Enclosure:

Copy of announcement regarding Interim Results sent to the
London Stock Exchange on 17 November 2004.






press release

PR0442

            INTERIM RESULTS FOR THE 6 MONTHS ENDED 30 SEPTEMBER 2004

Released: 17 November 2004

- -  Strong first-half performance delivered across the Group(1):

   - Customer base grew 15% to 22.0 million (2003 : 19.2 million);
   - Group turnover grew 23% to GBP3,285 million (2003 : GBP2,680 million);
   - EBITDA grew 37% to GBP851 million (2003 : GBP621 million);
   - Group operating profit increased to GBP251 million (2003 : GBP66 million);

- -  Basic earnings per share increased to 2.7 pence (2003 : 0.3 pence)

- -  Underlying earnings per share(2) increased to 4.5 pence (2003 : 1.5 pence)

- -  Group net debt reduced by GBP130 million during first half, to
   GBP236 million.

- -  O2 UK full-year net service revenue growth now expected to be 12 - 15%.

- -  Increased network investment in Germany of EUR1.0 - EUR1.5 billion over
   5 years

- -  New policy of regular, sustainable dividends based on underlying EPS

   - Final dividend expected to be declared in May 2005 and paid in August 2005
   - Medium term target payout ratio 50%

- -  Corporate reorganisation to create distributable reserves before end FY 05


(1) Continuing operations. Comparative period is 6 months to 30 September 2003.
(2) Before goodwill and UMTS licence amortisation and exceptional items.

David Arculus, Chairman of mmO2 plc, commented:

"In the first half mmO2 delivered another good performance, with strong revenue
and EBITDA growth. Over the past three years there has been a transformation in
the Group's operational and financial performance, and we are very pleased now
to be able to establish a policy of sustainable dividends, earlier than
originally expected. The Group has delivered earnings growth and positive
cash-flow, and we believe strongly that shareholders should benefit directly
from this. The new policy reflects our confidence in the company's future
prospects, and our commitment to deliver returns for shareholders."




Financial highlights
                                Six months     Six months           Year ended
                                     ended          ended             31 March
                             30 Sept. 2004  30 Sept. 2003                 2004
                                     GBPm           GBPm                  GBPm
                                                                 

- --------------------------------------------------------------------------------
Turnover (1)                        3,285          2,680                 5,646
EBITDA (1)                            851            621                 1,367
Group operating profit (1)            251             66                   159
Basic earnings per share (pence)      2.7            0.3                   1.9
Underlying earnings per
share (pence)(2)                      4.5            1.5                   5.2
- --------------------------------------------------------------------------------
Capital expenditure                   656            539                 1,213
Net debt                              236            494                   366
- --------------------------------------------------------------------------------


(1) Continuing operations.
(2) Before goodwill and UMTS licence amortisation and exceptional items.


Peter Erskine, Chief Executive of mmO2 plc, commented:

"In the first half mmO2 has delivered further strong revenue and profit growth,
across all our businesses. Despite robust competition in all our mobile markets,
year-on-year we have delivered a 15% increase in the customer base, 23% revenue
growth, 37% growth in EBITDA, and a Group operating profit of GBP251 million.
Underlying earnings per share, the measure on which we intend to base our
dividends, increased three-fold, to 4.5 pence per share. Our net debt was
reduced by a further GBP130 million, to GBP236 million.

The strategic development we have announced in Germany, investing to grow the
business further and to accelerate the roll-out of our 3G network, builds on the
strength of the O2 brand and the position we have established as the most
dynamic and innovative competitor in the German market. Increasing network
investment will enable us to offer an enhanced customer experience in Germany,
with attractive and high quality mobile services delivered across our own 3G
platform. This will increase our long-term margins, driving revenue growth and
reducing operating costs.

Although the UK market remains highly competitive, our growth through the end of
the first half has remained significantly stronger than expected, and we now
expect to see full year net service revenue growth of 12-15%, higher than we had
previously anticipated. "

Performance highlights - First Half (1)

O2 UK:

   - Total customer base grew by 10% to 13.86 million
   - Service revenue grew by 20% to GBP1,848 million
   - EBITDA grew by 21% to GBP581 million
   - EBITDA margin 28.5% (2) (2003: 29.2%)

O2 Germany:

   - Total customer base grew by 27% to 6.67 million, of which 58% post-pay
   - At constant exchange rates, service revenue grew by 29%
   - EBITDA grew by 50% to GBP163 million
   - EBITDA margin improved to 18.6% (2003: 15.1%)

O2 Ireland:

   - Total customer base grew by 12% to 1.43 million
   - At constant exchange rates, service revenue grew by 14%
   - EBITDA GBP106 million (2003 : GBP103 million)
   - EBITDA margin 37.9% (2003: 39.6%)

Airwave:

   - Roll-out on track, with service delivered to 40 police forces
   - Revenue GBP76 million (2003 : GBP25 million)
   - EBITDA GBP24 million (2003 : GBP(15) million)

(1) Comparative period: 6 months to 30 September 2003.
(2) Reflects impact of transfer to O2 UK of O2 Online/Products O2 costs,
previously reported separately.

Operational highlights - Second Quarter

Group:

   - Customer base grew by 3% quarter-on-quarter, to 22.0 million
   - 714,000 net new customers added (Q1 : 603,000), of which 45% post-pay

O2 UK:

   - 331,000 net new customers added (Q1 : 261,000), of which 127,000 post-pay
   - Blended ARPU GBP282 (Q1 : GBP279)

O2 Germany:

   - 351,000 net new customers added (Q1 : 336,000), of which 186,000 post-pay
   - Blended ARPU EUR371 (Q1 : EUR367)

O2 Ireland:

   - 30,000 net new customers added (Q1 : 4,000), of which 5,000 post-pay
   - Blended ARPU EUR560 (Q1 : EUR556)

Mobile data:

   - Data as a proportion of service revenue 21.9% (Q1: 21.2%)
   - Total SMS sent grew by 4.3% in the quarter to 3.359 billion




SUMMARY FINANCIAL DATA



Turnover

                             Six months ended    Six months ended   Year ended
                            30 September 2004   30 September 2003     31 March
                                                                          2004
Continuing operations                    GBPm                GBPm         GBPm
                                                                  

- --------------------------------------------------------------------------------
O2 UK                                   2,037               1,651        3,451
O2 Germany                                877                 719        1,508
O2 Ireland                                280                 260          529
Airwave                                    76                  25           89
Manx                                       25                  25           50
O2 Online & Products O2                     -                  54          140
Eliminations                              (10)                (54)        (121)
- --------------------------------------------------------------------------------
Group total                             3,285               2,680        5,646
- --------------------------------------------------------------------------------





EBITDA

                             Six months ended    Six months ended   Year ended
                            30 September 2004   30 September 2003     31 March
                                                                          2004
Continuing operations                    GBPm                GBPm         GBPm
                                                                  
- --------------------------------------------------------------------------------
O2 UK                                     581                 482        1,041
O2 Germany                                163                 109          225
O2 Ireland                                106                 103          208
Airwave                                    24                 (15)           1
Manx                                       11                  11           23
O2 Online & Products O2                     -                 (25)         (43)
Central resources                         (34)                (44)         (88)
- --------------------------------------------------------------------------------
Group total                               851                 621        1,367
- --------------------------------------------------------------------------------





Operating profit/(loss)

                                Six months ended   Six months ended Year ended
                               30 September 2004  30 September 2003   31 March
                                                                          2004
                                           GBPm               GBPm        GBPm
                                                                  
- --------------------------------------------------------------------------------
O2 UK                                       341                243         552
O2 Germany                                   16                (35)        (70)
O2 Ireland                                   74                 67         140
Airwave                                       2                (23)        (30)
Manx                                          8                  8          17
O2 Online & Products O2                       -                (49)        (83)
Central resources                           (40)               (44)        (91)
- --------------------------------------------------------------------------------
Operating profit before
goodwill and UMTS licence
amortisation and
exceptional items, from
continuing operations                       401                167         435

Operating loss from
discontinued operations                       -                 (1)         (1)

Goodwill amortisation                      (100)              (101)       (201)

UMTS licence amortisation                   (50)                 -           -

Exceptional items                             -                  -         (75)
- --------------------------------------------------------------------------------
Group operating profit                      251                 65         158

Share of operating loss
of joint ventures and
associates                                   (4)                (2)          -

Loss on sale of O2 Netherlands                -                 (5)         (5)

Net interest                                 (8)               (32)        (58)

Tax                                          (3)                (3)         71
- --------------------------------------------------------------------------------
Retained profit for the period              236                 23         166
- --------------------------------------------------------------------------------
Basic earnings per share (pence)            2.7                0.3         1.9
- --------------------------------------------------------------------------------
Underlying earnings per share (pence)       4.5                1.5         5.2
- --------------------------------------------------------------------------------





Capital expenditure

                               Six months ended  Six months ended   Year ended
                                   30 September      30 September     31 March
                                           2004              2003         2004
Continuing operations                     GBPm               GBPm         GBPm
                                                                  
- --------------------------------------------------------------------------------
O2 UK                                      292                217          502
O2 Germany                                 130                132          308
O2 Ireland                                  42                 24           52
Airwave                                    128                158          243
Manx                                         4                  1            9
O2 Online & Products O2                      -                  7           14
Central resources                            3                  -            2
- --------------------------------------------------------------------------------
Group total excluding
German network sharing agreement           599                539        1,130
German network sharing agreement            57                  -           83
- --------------------------------------------------------------------------------
Group total                                656                539        1,213
- --------------------------------------------------------------------------------


GROUP FINANCIAL RESULTS

Profit and loss account

In the first half  Group  turnover  from  continuing  operations  grew by 23% to
GBP3,285  million,  driven by strong  customer growth and higher ARPU across the
three  mobile  operating  businesses,  and the  further  roll-out of the Airwave
network. EBITDA before exceptional items increased by 37% to GBP851 million, and
the Group  EBITDA  margin  improved to 25.9%,  from 23.2% in the first half last
year.

Operating profit from continuing operations,  before goodwill, UMTS licences and
exceptional  items,  more than  doubled to GBP401  million,  compared  to GBP167
million in the first half last year. UMTS licence  amortisation of GBP50 million
was charged in the half-year,  reflecting  the  commercial  launch of UMTS-based
services by O2 Germany at the start of May.  No UMTS  licence  amortisation  was
charged by O2 UK or O2 Ireland.

There were no  exceptional  charges in the first half.  The Group's share of the
operating  results of its joint  ventures and associates in the first half was a
net loss of GBP4 million,  compared to a loss of GBP2 million last year,  mainly
reflecting the costs of growing the Tesco Mobile  customer base. The Group's net
interest charge was reduced  significantly,  to GBP8 million, from GBP32 million
in the first half last year. This was due to a number of factors,  including the
fall in net debt,  and narrowing of the spread  between the interest  payable on
the Group's  gross debt and the  interest  receivable  on its cash  balance.  In
addition,  the Group's foreign exchange hedging strategy resulted in a reduction
in interest payable of GBP8 million.

Profit  before  tax was  GBP239  million in the first  half,  compared  to GBP26
million in the same period  last year.  The tax charge was GBP3  million.  Basic
earnings per share in the  half-year  were 2.7 pence,  compared to 0.3 pence for
the first half last year.  Underlying  earnings per share,  before  goodwill and
UMTS licence  amortisation,  and exceptional  items, grew to 4.5 pence, from 1.5
pence in the same period last year.

Distribution policy update

To reflect the Group's continuing growth in earnings and cash-flow,  at the time
of the Preliminary Results announcement in May 2005 the Board expects to declare
an inaugural final dividend for the current financial year, to be paid in August
2005, following approval by shareholders at the Annual General Meeting.

Going  forward,  the  Board is  committed  to  implement  a policy  of  regular,
sustainable  dividends,  growing by reference to the Group's underlying earnings
per  share  (i.e.  before  goodwill  and  UMTS  licence  amortisation),  with  a
medium-term  target  payout  ratio of 50%.  From the  beginning  of the  2005/06
financial year the Board intends to pay an interim dividend in January and final
dividend in August, split approximately one-third/two-thirds.

To ensure  the Group has  sufficient  distributable  reserves  to  support  this
distribution  policy,  the Group  will  undertake  a  corporate  reorganisation,
through a Court  approved  Scheme of arrangement  and reduction of capital.  The
Scheme will be subject to  shareholder  approval  at an EGM,  expected to become
effective before the end of the current financial year.

Capital expenditure and net debt

Group capital  expenditure  in the first half  increased by GBP117  million,  to
GBP656  million,  and included a further  payment of GBP57 million in respect of
the network sharing agreement in Germany.  Higher spending in the UK and Ireland
was driven by increased investment in the UMTS network roll-out.

Group net debt was further  reduced,  to GBP236  million at the end of the first
half, compared to GBP366 million at the start of the year, and GBP494 million at
the same time last year, with the increased capital expenditure more than offset
by EBITDA growth.

Investment programme - O2 Germany

Building on its operational  and financial  turnaround over the past three years
and its strengthened position in the market, O2 Germany will now aim to grow its
business further,  and will increase investment in its UMTS network.  During the
five-year  period  from April 2004 O2 Germany  is now  expected  to incur  total
capital expenditure in the range EUR3.0 to EUR3.5 billion,  aiming to deliver 3G
network quality and long-term  population  coverage that is competitive with the
market leaders.  This is EUR1.0 to EUR1.5 billion higher than under the previous
strategy,  and the cash-flow impact will to a significant  extent be offset by a
reduction in operating costs,  and further revenue growth.  Growing the business
rapidly,  and  reducing  operating  costs,  will  position O2 Germany to deliver
higher long-term margins.

BUSINESS REVIEW

O2 UK

Interim results

In the first  half O2 UK  delivered  further  strong  growth,  with net  service
revenue up by 20%  year-on-year to GBP1,848  million.  The termination  rate cut
incurred at the  beginning of September  reduced  first half service  revenue by
approximately  GBP20  million.  Equipment and  wholesale  revenue grew by 62% to
GBP189 million.  Total revenue in the first half was GBP2,037 million, 23% ahead
of the first half last year.

EBITDA increased by 21% to GBP581 million and the EBITDA margin was 28.5%. First
half EBITDA included the O2  Online/Products  O2 costs which had previously been
reported   separately,   and  which  reduced  the  reported   EBITDA  margin  by
approximately  1%.  The 28.5%  EBITDA  margin in the  first  half was  therefore
slightly ahead of last year, on a like-for-like basis. The revenue impact of the
termination rate cut was partially offset by a reduction in termination payments
to other mobile network operators,  with no significant impact on O2 UK's EBITDA
margin.

First half operating  profit,  before  exceptionals  and goodwill,  increased by
GBP98 million to GBP341 million. No UMTS licence amortisation was charged in the
first half.

Service  revenue  growth in the first half was driven by growth of the  customer
base and by higher ARPU.  The total  customer  base at the end of the first half
grew by 10% to 13.86 million,  and the  proportion of contract  customers in the
base  increased  to 35%,  from  34.3% at the end of the first  half  last  year.
Blended  ARPU at the end of the first  half grew to GBP282,  from  GBP272 at the
start of the year, and GBP259 at the same time last year.

Voice and data both  contributed  to O2 UK's  service  revenue  growth.  Blended
average voice minutes of use per customer was 131 minutes per month, 6.5% higher
than at the start of the year, and 13.9% higher than at the same time last year.
Blended data ARPU was GBP62 on a 12-month  rolling  basis,  compared to GBP55 at
the start of the year.

Subscriber acquisition and retention costs accounted for 15.6% of first half
total revenue, compared to 15.8% in the first half last year. However the first
half EBITDA margin before SAC and SRC was reduced to 44.1%, from 45.0% last
year, reflecting the inclusion of the costs of O2 Online/Products O2 from the
start of the current year.

Capital  expenditure  in the first half  increased by GBP75  million,  to GBP292
million.  This mainly  reflected  acceleration of O2 UK's UMTS network  roll-out
programme, which accounted for approximately one third of total capital spending
in the  first  half.  O2 UK's  new  customer  relationship  and  billing  system
accounted for around 15% of the total.

Second quarter key performance indicators

A total of 331,000 net new customers were added in the quarter, of which 127,000
were contract  customers.  Contract ARPU improved to GBP541,  from GBP537 in the
first quarter,  and pre-pay ARPU  increased to GBP145,  from GBP143 in the first
quarter,  reflecting  O2 UK's  continued  success  in  attracting  higher  value
customers in both markets.  The  termination  rate cut at the start of September
reduced second quarter blended rolling ARPU by GBP2.

O2 UK continued to make gains in the business market, with investment in direct
channels and development of specific propositions for targeted customer segments
proving successful. These included the "O2 Welcome" service for corporate
customers and the "Business Zones" proposition for the SME segment. In the
contract consumer market, additions to the "X" range of O2 branded handsets and
promotions such as "Happy Hour" attracted high-value customers. Contract churn
deteriorated in the quarter to 27%, on a 12-month rolling basis, compared to 26%
at the end of March. Contract SAC was slightly higher than in the second quarter
last year, but was more than offset by the improved contract ARPU being
generated across the base.

Targeted tariff propositions and the handset mix continued to attract high value
pre-pay customers, particularly in the youth market. The development of new
"Bolt-on" packages, and propositions such as "O2 Thanks" and the new "X" range
of devices, kept the pre-pay offer fresh. The intensity of competition was
reflected in pre-pay churn, which increased again in the quarter. However
pre-pay SAC was stable.

The importance of O2's own channels continued to increase, and accounted for 48%
of gross sales in the second quarter, compared to 40% in the second quarter last
year. The O2 brand continued to drive high value customer acquisition in target
market segments, and this was recognised in November when O2 UK won the IPA's
2004 Grand Prix for advertising and brand effectiveness.

The total number of text messages sent in the quarter grew by 5.2%
quarter-on-quarter, to 2.47 billion. Data as a proportion of O2 UK's total
service revenue increased to 23.0%, from 21.3% in the first quarter. The growth
of picture messaging continued, with 9.8 million messages sent by O2 UK
customers in the quarter, compared to 6.4 million in first quarter. Non-SMS data
accounted for 2.4% of total service revenue in the quarter, double the
proportion in the same quarter last year.

O2 Germany

Interim results

O2 Germany  continued  to grow  strongly  during the first  half,  with  service
revenue up 29% at constant  exchange  rates, to EUR1,184  million (2003:  EUR921
million).  Total revenue was GBP877  million,  compared to GBP719 million in the
first half last year. First half EBITDA increased to GBP163 million, from GBP109
million in the same period last year,  and the EBITDA margin  improved to 18.6%,
from 15.1% last year.

The operating profit before goodwill, UMTS licence and exceptionals was GBP16
million, compared to a loss of GBP35 million last year. O2 Germany started to
amortise its UMTS licence in May, and the total first half charge was GBP50
million.

The main driver of revenue growth was the continuing rapid growth in customer
numbers. A total of 687,000 net new customers were added during the first half,
taking the total base to 6.67 million at the end of the period, compared to 5.25
million at the same time last year. The customer mix continued to improve, with
contract customers comprising 57.9% of the base at the end of the first half, up
from 56.8% last year.

Blended  ARPU of EUR371 at the end of the first half was EUR5 higher than at the
start of the year,  and EUR17  ahead of the same time last year.  ARPU growth in
the first half was driven  mainly by data,  with data ARPU  increasing to EUR76,
from EUR71 at the start of the year,  reflecting  further  strong growth in text
messaging.  Voice usage also continued to grow, with minutes of use per customer
increasing by 6% compared to the same period last year, to 120 minutes/month.

The main driver of O2 Germany's continuing success in attracting high value
contract customers remains the Genion Homezone service. At the end of the first
half 75% of O2 Germany's contract customers subscribed to this service. Contract
churn remained stable during the first half, but contract acquisition cost per
subscriber increased, reflecting competitive pressure in the contract consumer
market.

O2 Germany increased its focus on the pre-pay market in the first half,
accelerating the rate of growth of the pre-pay base, while holding pre-pay ARPU
steady at EUR138. Pre-pay churn remained stable during the first half, but the
increased focus on this market was reflected in an increase in pre-pay
acquisition costs per customer. At the end of the period a distribution and
marketing joint-venture with Tchibo was announced, to further build O2 Germany's
position in the pre-pay market.

Subscriber acquisition and retention costs represented 20.4% of total revenue in
the first half, compared to 19.2% in the first half last year. The first half
EBITDA margin before SAC and SRC improved to 39.0%, from 34.3% in the first half
last year and 37.5% in the second half. National roaming payments in the first
half were GBP35 million, compared to GBP32 million last year.

Capital expenditure in the first half was flat, year-on-year, at GBP130 million,
excluding a payment of GBP57 million to T-Mobile in respect of the extended
network sharing agreement. O2 Germany's investment in its own UMTS network
accounted for approximately 40% of capital expenditure in the first half.

Second quarter key performance indicators

A total of 351,000 net new customers were added in the quarter, of which 186,000
were  contract  customers.  Pre-pay ARPU was  unchanged  quarter-on-quarter,  at
EUR138.  Contract  ARPU in the  second  quarter  recovered  by EUR3,  to EUR540,
following the EUR3 decline  reported in the first  quarter.  Blended ARPU in the
second quarter was EUR4 ahead, at EUR371.

Data ARPU  accounted for around half of the  quarter-on-quarter  improvement  in
total ARPU,  improving by EUR2 to EUR76.  A total of 556 million  text  messages
were sent in the second  quarter,  5% higher than in the first quarter,  and 31%
more than in the second  quarter last year.  Mobile data  accounted for 20.4% of
second quarter service revenue.

Investment programme

Building on its operational  and financial  turnaround over the past three years
and its strengthened position in the market, O2 Germany will now aim to grow its
business further,  and will increase investment in its UMTS network.  During the
five-year  period  from April 2004 O2 Germany  is now  expected  to incur  total
capital expenditure in the range EUR3.0 to EUR3.5 billion,  aiming to deliver 3G
network quality and long-term  population  coverage that is competitive with the
market leaders.  This is EUR1.0 to EUR1.5 billion higher than under the previous
strategy,  and the cash-flow impact will to a significant  extent be offset by a
reduction in operating costs,  and further revenue growth.  Growing the business
rapidly,  and  reducing  operating  costs,  will  position O2 Germany to deliver
higher long-term margins.

O2 Ireland

Interim results

In the first half O2 Ireland's  service revenue grew by 14% at constant exchange
rates, to EUR401 million.  Total revenue was GBP280 million,  compared to GBP260
million  last year.  EBITDA in the first half was GBP106  million,  compared  to
GBP103  million in the same period last year,  and the EBITDA margin  reduced to
37.9%,  from  39.6% in the first half of last year.  This  reflected  the higher
level of  customer  additions  during  the  period,  an  increase  in  retention
spending,  and some additional UMTS network  operating  costs.  Operating profit
before  goodwill and  exceptionals  increased by 10% in the first half, to GBP74
million. No UMTS licence amortisation was charged in the first half.

The main driver of growth was new customer acquisition, with the base growing by
12%  year-on-year  to 1.425  million,  of which 27.6% were  contract  customers.
Blended  ARPU grew by 1.6%,  to EUR560.  This was driven by both voice and data,
with average minutes of use per customer  increasing to 203 per month,  from 192
at the same time  last  year,  and data ARPU 8% higher  than at the start of the
year, at EUR119.

Second quarter key performance indicators

A total of 30,000 net new  customers  were added in the quarter,  of which 5,000
were contract  customers.  Second quarter  blended ARPU was EUR560,  compared to
EUR556 in the first quarter.  Contract ARPU grew by 2.4% quarter-on-quarter,  to
EUR1,078. Pre-pay ARPU was EUR360, compared to EUR361 in the first quarter.

Blended data ARPU was EUR119, EUR1 higher than in the first quarter.  The number
of text messages was broadly flat, quarter on quarter, at 323 million,  and data
as a  proportion  of  service  revenues  fell to 19.0%  from  21.8% in the first
quarter, reflecting the stronger growth of voice usage in the quarter.

O2 Airwave

The network roll-out continued on track, and by the end of the first half the
service had been successfully delivered to 40 of Britain's 51 police forces. The
build programme remains on track to complete roll-out of the network to the
remaining police forces by the end of the financial year.

Revenue in the first half  increased to GBP76  million,  from GBP25 million last
year. EBITDA was GBP24 million,  compared to a loss of GBP15 million in the same
period  last year,  and  Airwave  delivered  its first  operating  profit,  GBP2
million,  compared  to a loss of GBP23  million  in the first  half  last  year.
Capital  expenditure  in the first half was GBP128  million,  compared to GBP158
million last year.

O2 Airwave has been short-listed for the national contracts to supply
communications services to the UK's Fire and Ambulance services. Despite some
delays in the tendering process, these contracts are currently expected to be
awarded to the winning bidder during the first half of 2005. O2 Airwave is also
bidding for a number of other contracts.


OUTLOOK STATEMENT

Year ending 31 March 2005:

- - O2 UK

The UK market remains intensely competitive, and the migration of the BT own-use
customers off the network will put further pressure on subscriber growth in the
second half. However O2 UK's performance through the end of the first half and
into the second half has been stronger than expected, in spite of the
approximately 30% cut in termination rates implemented at the beginning of
September. Voice and data usage have continued to grow, without being subject to
significant yield erosion. The Group therefore now expects O2 UK to report net
service revenue growth for the full year in the range 12-15%, compared to the
previously guided range of 9-12%.

The Group continues to expect the full-year EBITDA margin in 2004/05 to remain
stable, on a like-for-like basis. O2 UK commenced amortisation of its UMTS
licence at the start of October, and the charge for the full year is expected to
be GBP57 million.

- - O2 Germany

For the full-year the Group continues to expect O2 Germany to deliver further
strong revenue growth, and to achieve an EBITDA margin in the high teens.

- - O2 Ireland

For the full-year the Group continues to expect O2 Ireland to report further
steady growth of service revenue and EBITDA, and a broadly stable EBITDA margin
for the full year.

- - Capital expenditure

The Group continues to expect capital expenditure for the full year to be in the
range  GBP1.3 - GBP1.4  billion.  The  increase  over the  previous  year mainly
reflects higher UMTS investment in the UK.

Capital expenditure in the full year by O2 Germany is now expected to be
slightly higher than last year, reflecting the start of the acceleration of the
roll-out of the UMTS network.

Airwave's capital expenditure in the full year is now expected to be in line
with last year, rather than higher, as previously guided. This reflects the
delays in concluding the Fire and Ambulance contracts, for which Airwave had
expected to incur capital expenditure in the current financial year.

O2 Germany - five-year investment programme

During the  five-year  period  from  April 2004 the Group  expects O2 Germany to
incur total capital expenditure in the range EUR3.0 to EUR3.5 billion,  which is
EUR1.0 to EUR1.5  billion higher than under the previous  strategy,  and aims to
achieve UMTS network  quality and population  coverage that is competitive  with
the market leaders.  The cash flow impact of the increase in capital expenditure
over the five-year period will to a significant  extent be offset by a reduction
in operating costs, and further revenue growth.

Capital structure

The Group intends to maintain  financial  ratios  consistent  with an investment
grade credit  rating of strong  BBB/Baa.  At the end of the first half the Group
had net debt of GBP236 million and operating lease  commitments of approximately
GBP1.8 billion.  Following the recently  completed renewal and re-pricing of its
banking  facilities,  the  Group  now  has a  GBP1.0  billion  revolving  credit
facility,  maturing in October  2009,  which  represents  a reduction  of GBP825
million in its overall bank facilities.

The Board will continue to review the company's balance sheet, in the light of
the medium-term capital requirements of the business and its commitment to
investment grade credit status.

CORPORATE RE-ORGANISATION

As a consequence of the structure of the demerger in 2001, mmO2 currently lacks
distributable reserves. This could restrict the Group's ability to pay future
dividends. Therefore, the Group proposes to implement a corporate
reorganisation, by way of a Court approved Scheme of arrangement under s.425 of
the Companies Act 1985.

Under the Scheme it is intended that a new parent company will be created,
NewCo, which will acquire all of the shares in mmO2 plc, by issuing new NewCo
shares. At the same time NewCo will effect a capital reduction, in order to
provide it with the distributable reserves required to support the distribution
policy described above.

The Board also intends to explore options to offer the large number of very
small shareholders the opportunity to monetise their holdings without incurring
transaction costs. This would reduce the administrative costs that would be
incurred in making regular dividend payments. In addition, the Board intends to
review the status of its US ADR programme, which has been in decline over the
past three years.

The Scheme will require Court and shareholder approval, which will be sought at
a meeting to be convened by the Court, and an EGM. The Scheme is expected to
become effective before the end of the current financial year.

Cautionary statement Regarding Forward-Looking Statements

This document contains certain forward-looking statements. We may also make
written or oral forward-looking statements in:

- -   our periodic reports to the US Securities and Exchange Commission, also
    known as the SEC, on Forms 20-F and 6-K;

- -   our annual report and accounts and half-yearly reports;

- -   our press releases and other written materials; and

- -   oral statements made by our officers, directors or employees to third
    parties.

We have based these forward-looking statements on our current plans,
expectations and projections about future events. These forward-looking
statements are subject to risks, uncertainties and assumptions about us.
Forward-looking statements speak only as of the date they are made.

Statements that are not historical facts, including statements about our beliefs
and expectations are forward-looking statements. Words like "believe,"
"anticipate," "expect," "intend," "seek," "will," "plan," "could," "may,"
"might," "project," "goal," "target" and similar expressions often identify
forward-looking statements but are not the only ways we identify these
statements.

These statements may be found in this document generally. Our actual results
could differ materially from those anticipated in these forward-looking
statements as a result of various factors, including all the risks discussed in
the above-mentioned sections.

If any one or more of the foregoing assumptions are ultimately incorrect, our
actual results may differ from our expectations based on these assumptions.
Also, the sector and markets in which we operate may not grow over the next
several years as expected, or at all. The failure of these markets to grow as
expected may have a material adverse effect on our business, operating results
and financial condition and the market price of our ordinary shares and ADSs.

The information on our web site, any web site mentioned in this document or any
web site directly or indirectly linked to our or any other web site mentioned in
this document is not incorporated by reference into this document and you should
not rely on it.



Interim statement for the six months ended 30 September 2004




Group profit and loss account
Six months ended 30 September 2004 (unaudited)

                               Note       Six months       Six months     Year
                                               ended            ended    ended
                                        30 September     30 September 31 March
                                                2004             2003     2004
                                                GBPm             GBPm     GBPm
                                                                

- --------------------------------------------------------------------------------
Turnover: group and
share of joint
ventures and associates                        3,374            2,794    5,859

Group's share of joint
ventures and associates
turnover                                         (89)             (66)    (165)
- --------------------------------------------------------------------------------
Group turnover                  2,3            3,285            2,728    5,694

Net operating expenses
(including exceptional
items)                                        (3,034)          (2,663)  (5,536)

EBITDA 1                                         851              621    1,367
Depreciation before
exceptional items                               (413)            (449)    (926)

Goodwill amortisation                           (100)            (101)    (201)

Other amortisation                               (87)              (6)      (7)
- --------------------------------------------------------------------------------
Operating profit before
exceptional items                                251               65      233

Exceptional items                 4                -                -      (75)
- --------------------------------------------------------------------------------
Group operating profit            3              251               65      158

Group's share of operating
loss of joint ventures and
associates                                        (4)              (2)       -
- --------------------------------------------------------------------------------
Total operating profit                           247               63      158

Loss on sale of business -
discontinued operations           4                -               (5)      (5)

Net interest payable and
similar charges                                   (8)             (32)     (58)
- --------------------------------------------------------------------------------
Profit on ordinary
activities before taxation                       239               26       95

Tax on profit on ordinary
activities                        5               (3)              (3)      71
- --------------------------------------------------------------------------------
Retained profit after
taxation for the period                          236               23      166
- --------------------------------------------------------------------------------
Basic and diluted
earnings per
share (pence)                     6              2.7              0.3      1.9
- --------------------------------------------------------------------------------



1 EBITDA is our earnings before interest, tax, depreciation, amortisation and
exceptional items, excluding our share of operating profits and losses of our
joint ventures and associates. EBITDA is not a measure of financial performance
under UK or US GAAP and may not be comparable to similarly titled measures of
other companies, because EBITDA is not uniformly defined. EBITDA should not be
considered by investors as an alternative to Group operating profit or profit on
ordinary activities before taxation as an indication of operating performance,
or as an alternative to cash flow from operating activities as an indication of
cash flows. EBITDA is one of the key financial measures used by the Group for
evaluating financial performance.





Group statement of total recognised gains and losses
Six months ended 30 September 2004 (unaudited)

                              Note        Six months     Six months       Year
                                            ended 30       ended 30      ended
                                           September      September   31 March
                                                2004           2003       2004
                                               GBPm            GBPm       GBPm
                                                              

- --------------------------------------------------------------------------------
Profit for the financial
period                            9             236              23        166

Currency translation
differences arising on
foreign currency net
investments in subsidiaries
less translation
differences on debt
designated as a hedge of
foreign currency net
investments                       9              71              75       (144)
- --------------------------------------------------------------------------------
Total recognised
gains relating to the
period                                          307              98         22
- --------------------------------------------------------------------------------







Group balance sheet
As at 30 September 2004 (unaudited)

                              Note    30 September   30 September    31 March
                                              2004           2003        2004
                                                     As restated*  As restated*
                                              GBPm           GBPm        GBPm
                                                              
- --------------------------------------------------------------------------------
Fixed assets
Intangible assets                            7,309          7,524       7,354
Tangible assets                              4,218          3,959       3,996
Investments                                      4              4           5
- --------------------------------------------------------------------------------
                                            11,531         11,487      11,355
- --------------------------------------------------------------------------------
Current assets
Stocks                                         108             71          84
Debtors                                      1,131          1,067         943
Investments                                  1,163            927         993
Cash at bank and in hand                        30             41          23
- --------------------------------------------------------------------------------
                                             2,432          2,106       2,043
Creditors: amounts
falling due within
one year                                    (1,920)        (1,703)     (1,678)
- --------------------------------------------------------------------------------
Net current assets                             512            403         365
- --------------------------------------------------------------------------------
Total assets less
current liabilities                         12,043         11,890      11,720
- --------------------------------------------------------------------------------
Creditors: amounts
falling due after
more than one year                          (1,423)        (1,441)     (1,375)

Provisions for
liabilities and
charges                                       (217)          (287)       (251)
- --------------------------------------------------------------------------------
Net assets                                  10,403         10,162      10,094
- --------------------------------------------------------------------------------
Capital and reserves
Called up share capital           9              9              9           9
Share premium                     9              4              -           3
Other reserves                    9         10,513         11,580      11,074
Profit and loss account           9           (123)        (1,427)       (992)
- --------------------------------------------------------------------------------
Equity shareholders' funds                  10,403         10,162      10,094
- --------------------------------------------------------------------------------


* Restated on the adoption of UITF 38 "Accounting for ESOP trusts" as disclosed
in note 9.





Reconciliation of operating profit to operating cash flows
Six months ended 30 September 2004 (unaudited)

                                 Six months               Six months     Year
                                   ended 30                 ended 30 ended 31
                                  September                September    March
                                       2004                     2003     2004
                                       GBPm                     GBPm     GBPm
                                                                   
- --------------------------------------------------------------------------------
Group operating profit                  251                       65      158
Depreciation and amortisation charges   600                      556    1,136
Loss on disposal of fixed assets          -                        1        5
Increase in stocks                      (23)                      (2)     (17)
Increase in debtors                    (169)                    (203)     (88)
Increase in creditors                   156                      157      142
(Decrease)/increase in provisions       (28)                       5       55
- --------------------------------------------------------------------------------
Net cash inflow from
operating activities                    787                      579    1,391
- --------------------------------------------------------------------------------






Group cash flow statement
Six months ended 30 September 2004 (unaudited)

                               Note        Six months      Six months     Year
                                             ended 30        ended 30    ended
                                            September       September 31 March
                                                2004             2003     2004
                                                GBPm             GBPm      GBPm
                                                              
- --------------------------------------------------------------------------------
Cash inflow from operating
activities                                       787              579    1,391

Returns on investments
and servicing of finance                          18              (24)     (62)

Taxation                                          (4)              (7)     (13)

Capital expenditure
and financial investment                        (637)            (480)  (1,114)

Acquisitions and disposals
(six months ended 30
September 2003 and year ended
31 March 2004: net of GBP10
million cash disposed of
with O2 Netherlands)                              -               (5)      (6)
- --------------------------------------------------------------------------------
Cash inflow before
management of liquid
resources and financing                          164               63      196

Management of liquid
resources                       7,8             (147)             (80)    (191)

Financing                                        (10)             (10)     (50)
- --------------------------------------------------------------------------------
Increase/(decrease) in cash
in the period                   7,8                7              (27)     (45)
- --------------------------------------------------------------------------------





Group net debt
As at 30 September 2004 (unaudited)

                               Note     30 September     30 September 31 March
                                                2004             2003     2004
                                                GBPm             GBPm     GBPm
                                                               

- --------------------------------------------------------------------------------
Cash at bank and in hand                          30               41       23
Current asset investments                      1,163              927      993
- --------------------------------------------------------------------------------
                                               1,193              968    1,016
Euro medium term
notes (net of issue costs)                    (1,056)          (1,028)  (1,012)

Loan notes                                        (7)             (17)      (8)

Obligations under
hire purchase contracts                         (333)            (379)    (325)

Other loans and borrowings                       (33)             (38)     (37)
- --------------------------------------------------------------------------------
Net debt                        7,8             (236)            (494)    (366)
- --------------------------------------------------------------------------------


1.      Basis of preparation

The interim statement is prepared in accordance with the accounting policies
expected to apply for the financial year ending on 31 March 2005. These policies
are unchanged from those set out in the Annual Report and Financial Statements
of the Group for the year ended 31 March 2004 with the exception of the adoption
by the Group of UITF Abstract No. 38 "Accounting for ESOP trusts" as disclosed
in note 9.

The interim statement is unaudited and does not constitute statutory financial
statements, but has been reviewed by the auditors whose report is reproduced on
page 23. The interim statement for the six months ended 30 September 2004 was
approved by the Directors on 16 November 2004.

The Group profit and loss account, statement of total recognised gains and
losses and the cash flow statement for the year ended, and the balance sheet and
statement of net debt as at, 31 March 2004 as presented in this interim
statement are extracts from the statutory financial statements for that year,
which have been delivered to the Registrar of Companies. The report of the
auditors on the financial statements for the year ended 31 March 2004 was
unqualified and did not contain a statement under either section 237(2) or
section 237(3) of the Companies Act 1985.

2.      Segmental analysis

The segmental disclosures in respect of profit and loss account items are
presented below.



                                   Group   Depreciation and     Total operating
                                turnover       amortisation       profit/(loss)
                                    GBPm               GBPm               GBPm
                                                                 

- --------------------------------------------------------------------------------
Six months ended 30 September 2004

Continuing operations
Mobile telecommunications
                    UK             2,037                315                262
                    Germany          877                198                (35)
                    Ireland          280                 57                 49
- --------------------------------------------------------------------------------
Total mobile telecommunications    3,194                570                276
Other businesses    UK               101                 25                 10
Central overheads
and adjustments                        -                  5                (39)
Inter-segment eliminations           (10)                 -                  -
- --------------------------------------------------------------------------------
Group total                        3,285                600                247
- --------------------------------------------------------------------------------


Definition of segments

In the year ended 31 March 2004, the Group undertook a restructuring of its
central functions and rationalised its property portfolio. This included the
transfer of O2 Online, Products O2 and certain other central functions to the
Group's operating businesses in the UK, Germany and Ireland. In the six months
ended 30 September 2004, the activities of O2 Online and Products O2 which were
previously reported as the "mobile internet services" segment, are reported
within the segments in which they now reside. As the information is not readily
available, the comparatives have not been restated and these businesses are
reported separately in line with day-to-day managerial and budgetary control at
that time.

2. Segmental analysis continued



                                             Depreciation                Total
                                    Group             and            operating
                                 turnover    amortisation 1      profit/(loss)
                                     GBPm            GBPm                 GBPm
                                                                 

- --------------------------------------------------------------------------------
Six months ended 30 September 2003

Continuing operations
Mobile telecommunications
                   UK               1,651             314                  164
                   Germany            719             144                  (35)
                   Ireland            260              62                   41
- --------------------------------------------------------------------------------
Total mobile telecommunications     2,630             520                  170
Mobile internet
services           UK                  54              24                  (49)
Other businesses   UK                  50              11                  (15)
Central overheads
and adjustments                         -               -                  (42)
Inter-segment eliminations            (54)              -                    -
- --------------------------------------------------------------------------------
                                    2,680             555                   64
Discontinued operations
Mobile telecommunications
                   The Netherlands     48               1                   (1)
- --------------------------------------------------------------------------------
Group total                         2,728             556                   63
- --------------------------------------------------------------------------------

Year ended 31 March 2004

Continuing operations
Mobile telecommunications
                   UK               3,451             638                  346
                   Germany          1,508             295                  (72)
                   Ireland            529             120                   87
- --------------------------------------------------------------------------------
Total mobile telecommunications     5,488           1,053                  361
Mobile internet
services           UK                 140              42                  (93)
Other businesses   UK                 139              37                  (13)
Central overheads
and adjustments                         -               3                  (96)
Inter-segment eliminations           (121)              -                    -
- --------------------------------------------------------------------------------
                                    5,646           1,135                  159
Discontinued operations
Mobile telecommunications
                   The Netherlands     48               1                   (1)
- --------------------------------------------------------------------------------
Group total                         5,694           1,136                  158
- --------------------------------------------------------------------------------


1 In the year ended 31 March 2004, depreciation includes a charge of
GBP2 million included within exceptional operating costs.

Joint ventures and associates

Total turnover for the six months ended 30 September  2004 was GBP3,374  million
(year ended 31 March 2004: GBP5,859 million; six months ended 30 September 2003:
GBP2,794  million) and included GBP89 million (year ended 31 March 2004:  GBP165
million;  six months ended 30 September 2003:  GBP66 million)  representing  the
Group's  share of the turnover of its joint  ventures and  associates  in the UK
mobile  telecommunications  business. The Group's share of the operating loss of
its joint  ventures and  associates  was GBP4 million (year ended 31 March 2004:
nil; six months ended 30 September 2003: GBP2 million).

3.      Analysis of continuing and discontinued operations

The results for the six months ended 30 September 2004 derive entirely from
continuing operations. The analysis of results for the prior periods presented
is:



                                     Continuing          Discontinued
                                     operations            operations    Total
                                           GBPm                  GBPm     GBPm
                                                                   

- --------------------------------------------------------------------------------
Six months ended 30 September 2003
Group turnover                            2,680                    48    2,728
EBITDA                                      621                     -      621
Group operating profit/(loss)                66                    (1)      65
- --------------------------------------------------------------------------------
Year ended 31 March 2004
Group turnover                            5,646                    48    5,694
EBITDA                                    1,367                     -    1,367
Group operating profit/(loss)               159                    (1)     158
- --------------------------------------------------------------------------------



4.      Exceptional items

In the year ended 31 March 2004, the Group incurred an exceptional operating
charge of GBP75 million in respect of the restructuring described in note 2 and
included provisions relating to redundancies and the termination of property
leases. This charge gave rise to a cash outflow of GBP17 million in that year.

On 14 April 2003, the Group announced that it had agreed the sale of its
wholly-owned Dutch subsidiary, O2 Netherlands, to Greenfield Capital Partners,
an independent private equity and corporate finance group with existing
interests in the fixed telecoms sector, for EUR25 million cash. This sale was
completed on 3 June 2003 and took the form of the sale of all the issued shares
of O2 Netherlands. The total loss on sale arising on completion was GBP1,369
million which, after utilisation of the provision recognised in 2003, resulted
in a non-operating exceptional loss of GBP5 million.


5.      Tax on profit on ordinary activities



                                     Six months            Six months     Year
                                       ended 30              ended 30    ended
                                      September             September 31 March
                                           2004                  2003     2004
                                           GBPm                  GBPm     GBPm
                                                                  

- --------------------------------------------------------------------------------
United Kingdom  - current tax                 -                    (1)       -
                - deferred tax              (5)                   (1)     (84)
Overseas        -  current tax                7                     5       13
                - deferred tax                1                     -        -
- --------------------------------------------------------------------------------
Tax charge/(credit) on profit on
ordinary activities                           3                     3      (71)
- --------------------------------------------------------------------------------




6.      Earnings per share

Earnings per share has been calculated for all periods by dividing the profit
for the period by the weighted average number of ordinary shares in issue during
that period, as follows:



                                  Six months        Six months           Year
                                       ended             ended          ended
                                30 September      30 September       31 March
                                        2004              2003           2004
                                                                 
- --------------------------------------------------------------------------------
Profit for the period
(GBP million)                              236                23            166
- --------------------------------------------------------------------------------

Basic weighted average
share capital (number
of shares, million)                    8,672             8,670          8,671

Dilutive potential
ordinary shares
(number of shares,
million)                                  83                38             44
- --------------------------------------------------------------------------------
Diluted weighted
average share capital
(number of shares,
million)                               8,755             8,708          8,715
- --------------------------------------------------------------------------------
Basic and diluted
earnings per share
(pence)                                  2.7               0.3            1.9
- --------------------------------------------------------------------------------


Underlying earnings per share has been calculated using the basic weighted
average share capital and the underlying profit for the period calculated as
follows:



                                           Six months  Six months
                                             ended 30    ended 30   Year ended
                                            September   September     31 March
                                                 2004        2003         2004
                                                 GBPm        GBPm         GBPm
                                                                 

- --------------------------------------------------------------------------------

Profit on ordinary
activities after taxation                         236          23          166

Goodwill amortisation                             100         101          201
UMTS licence amortisation                          50           -            -
Exceptional items                                   -           5           80
- --------------------------------------------------------------------------------
Underlying earnings                               386         129          447
- --------------------------------------------------------------------------------
Underlying earnings
per share (pence)                                 4.5         1.5          5.2
- --------------------------------------------------------------------------------





7.      Analysis of net debt


                           At                                               At
                      1 April       Cash          Other non-cash  30 September
                         2004       flow               movements          2004
                         GBPm       GBPm                    GBPm          GBPm
                                                              

- --------------------------------------------------------------------------------
Cash at bank and in        23          7                       -            30
hand

Current asset             993        147                      23         1,163
investments
- --------------------------------------------------------------------------------
                        1,016        154                      23         1,193

Debt due after one     (1,043)         -                     (37)       (1,080)
year

Debt due within one       (14)         5                      (7)          (16)
year

Obligations under hire
purchase contracts       (325)         6                     (14)         (333)
- --------------------------------------------------------------------------------
                         (366)       165                     (35)         (236)
- --------------------------------------------------------------------------------





8.      Reconciliation of net cash flow to movement on net debt

                         Six months ended 30 Six months ended 30   Year ended 31
                              September 2004      September 2003      March 2004
                                        GBPm                GBPm          GBPm
                                                                  

- --------------------------------------------------------------------------------
Increase/(decrease) in cash
in the period                              7                 (27)          (45)

Management of liquid
resources                                147                  80           191

Cash outflow from decrease
in net debt                               11                  10            53
- --------------------------------------------------------------------------------
Decrease in net debt
resulting from
cash flows                               165                  63           199

Other non-cash
movements                                (35)                 (8)          (16)
- --------------------------------------------------------------------------------
Decrease in net debt in
the period                               130                  55           183

Net debt at beginning of
period                                  (366)               (549)         (549)
- --------------------------------------------------------------------------------
Net debt at
end of period                           (236)               (494)         (366)
- --------------------------------------------------------------------------------





9.      Reconciliation of movements in shareholders' funds

                      Called up    Share      Other    Profit    Total equity
                          share  premium   reserves       and    shareholders'
                        capital                          loss           funds
                                                      account
                          GBPm      GBPm       GBPm      GBPm             GBPm
                                                          

- --------------------------------------------------------------------------------
At 1 April 2003 as
previously reported          9         -     12,087    (2,030)          10,066

Prior period
adjustment
relating to
UITF 38                      -         -          -        (3)              (3)
- --------------------------------------------------------------------------------
At 1 April 2003 (as
restated)                    9         -     12,087    (2,033)          10,063

Retained
profit for the
year                         -         -          -       166              166

Transfer from
profit and
loss account                 -         -     (1,013)    1,013                -

Shares issued
on share scheme
exercise                     -         3          -         -                3

Share schemes
charge for the
period                       -         -          -         6                6

Currency
translation
differences                  -         -          -      (144)            (144)
- --------------------------------------------------------------------------------
At 31 March 2004 (as
restated)                    9         3     11,074      (992)          10,094

Retained
profit for the
period                       -         -          -       236              236

Transfer from
profit and
loss account                 -         -       (561)      561                -

Purchase of
mmO2 plc
ordinary
shares                       -         -          -        (1)              (1)

Shares issued
on share
schemes
exercise                     -         1          -         -                1

Share schemes
charge for the
period                       -         -          -         2                2

Currency
translation
differences                  -         -          -        71               71
- --------------------------------------------------------------------------------
At 30 September 2004         9         4     10,513      (123)          10,403
- --------------------------------------------------------------------------------


Prior period adjustment

The profit and loss account includes GBP3 million of own shares held at 30
September 2004 (31 March 2004: GBP2 million; 1 April 2003: GBP5 million).

The Group has adopted UITF Abstract 38 ("UITF 38") "Accounting for ESOP trusts"
in the six months ended 30 September 2004, which requires that a company's own
shares held through an ESOP trust be shown as a deduction from shareholders'
funds until such time as the shares vest unconditionally. Previously these
shares were recorded at cost less amortisation charged to date and shown as a
fixed asset investment.

The comparative figures in this interim statement have been restated to reflect
the adoption of UITF 38. The aggregate impact on the previously reported
figures, at 1 April 2003, is to reduce total equity shareholders' funds by GBP3
million (31 March 2004: increase total shareholders' funds by GBP3 million).
The adoption of UITF 38 has no effect on the profit and loss account.

Hedging strategy

The Group's treasury policy, including the approach to foreign currency
translation risk, is described in the Operating and financial review and
prospects on page 37 of the 2004 Annual Report and Accounts.

9. Reconciliation of movements in shareholders' funds continued

The overseas businesses of the Group, O2 Germany and O2 Ireland, conduct
substantially all their business in their domestic currency, Euros. As
anticipated in the 2004 Annual Report and Accounts, the cash flows in these
overseas businesses and the improved visibility of the future financial profile
of the Group has led us to increase the level of hedging of our overseas assets.
This was achieved through the redenomination of our existing Euro debt and the
use of EUR1,800 million forward foreign exchange contracts, which commenced in
June 2004.

The  redenomination  of existing  debt  realised a one-off cash inflow of GBP22m
which,  when combined with the revaluation of the relevant Euro denominated debt
at that time,  had no material  impact on net debt.  The  ongoing  effect of the
hedge  implementation is that the Euro borrowings,  which are a component of net
debt, are exposed to foreign exchange rate  fluctuations and the interest charge
is impacted by the forward  foreign  exchange  contracts,  which has reduced the
current  period  interest  charge by GBP8  million.  Additionally,  the  foreign
exchange gains or losses,  arising on the  retranslation  of the Euro borrowings
and on the forward foreign exchange  contracts,  are recognised in the statement
of total  recognised  gains  and  losses  as they  hedge  certain  assets of the
overseas  businesses.  The  statement  of total  recognised  gains and losses is
presented on page 14.

Full disclosure will be provided in the Group's 2005 Annual Report and Accounts
in accordance with FRS No. 13: "Derivatives and other financial instruments:
Disclosure".


10. International Financial Reporting Standards

The Council of the European Union announced in June 2002 that listed companies
in Europe would be required to adopt International Financial Reporting Standards
(IFRS) for accounting periods beginning on or after 1 January 2005. The adoption
of IFRS will apply to the Group for the first time for the half year ending 30
September 2005 and the year ending 31 March 2006.

In 2003, the Group formed a project team to manage the transition from existing
UK Generally Accepted Accounting Principles (UK GAAP) to IFRS. The project is
sponsored by the Chief Financial Officer and involves specialists from both the
Group Finance function as well as representatives from each of the Group's
operating businesses.

The initial phase of the project has been completed. This involved a high level
assessment of potential issues, the preparation of a project plan and
identification of the key work streams in the operating businesses and at a
group level, supported by work programmes in these areas. The Group has also
considered which, if any, of the optional transitional provisions within IFRS 1
"First time adoption of International Financial Reporting Standards" to adopt.
The second phase of the project, which is currently underway, involves the
restatement and reconciliation of opening balances to IFRS and the adjustment of
reporting systems to capture new data requirements for ongoing IFRS reporting.
We expect to publish full IFRS reconciliations in mid-2005 after the 31 March
2005 year end reporting is complete.

Our work on the project to date indicates that the major areas of difference
between UK GAAP and IFRS which will impact the Group include the following:

Goodwill

IFRS 3 "Business combinations" prohibits the annual amortisation of goodwill and
instead subjects such goodwill to an annual impairment review. The carrying
value of the Group's goodwill at the date of transition to IFRS is fixed and the
amortisation ceases from that date.

Intangible assets

IAS 38 "Intangible assets" considers, inter alia, whether an asset which
incorporates both tangible and intangible elements should be classed as a
tangible fixed asset or an intangible fixed asset. The treatment is determined
by an assessment of which element is more significant. It is likely that certain
of the Group's software, which is currently classed as a tangible fixed asset,
will be reclassified to intangible fixed assets.

Pension accounting

Under UK GAAP, the Group accounts for its pension schemes using SSAP 24 "Pension
costs" and has elected under the transitional rules of FRS 17 "Retirement
benefits" to make disclosures only. IAS 19 "Employee benefits" is similar, but
not identical to, FRS 17. IAS 19 and FRS 17 are conceptually different to SSAP
24 as they require any defined benefit pension scheme surplus or deficit to be
recognised on the Group's balance sheet.


10. International Financial Reporting Standards continued

On transition to IFRS, the Group expects to recognise the full assets and
liabilities of its defined benefit pension schemes on its balance sheet.
Thereafter, IAS 19 requires a portion of the surplus or deficit of defined
benefit pension schemes to be recognised on the Group balance sheet, based on
the application of a "corridor". This "corridor" is defined as the greater of
10% of the scheme's assets or liabilities, and actuarial gains and losses below
this threshold are not required to be recognised. Any actuarial gains and losses
exceeding the corridor are recognised in the profit and loss account over a
period representing the expected average remaining working lives of employees
participating in the scheme. Additionally, the profit and loss account charge
comprises an operating cost and an interest cost.

In April 2004, the IASB issued an exposure draft amending IAS 19 to allow
actuarial gains and losses to be recognised in full in the statement of changes
in equity, rather than in the profit and loss account, in the period in which
they arise.

The Group's principal pension scheme, the mmO2 Pension Plan, operates for the
majority of UK employees and is divided into defined benefit and defined
contribution sections. The defined benefit section comprises mainly active
members because all deferred and pensioner members at 30 June 2002 remained in
the BT Pension Scheme following the Group's demerger from BT in November 2001.
The assets of the mmO2 Pension Plan at 31 March 2004 were GBP278 million.

Accounting for share schemes

The Group has historically accounted for share scheme costs under UK GAAP using
the intrinsic value. IFRS 2 "Share based payments" requires the value of all
share based payments to be measured, and an expense recognised in the profit and
loss account, based on fair value. The fair value of the share schemes is
estimated using a valuation model and involves complex mathematical modelling.
It is often, but not always, the case that the fair value is higher than the
intrinsic value. Additionally, under UK GAAP, Inland Revenue approved SAYE
schemes are exempt from the requirement to recognise a charge whereas under IFRS
there is no such exemption.

Financial instruments

IAS 39 "Financial instruments: recognition and measurement" details how to value
and account for all financial instruments, including derivative instruments such
as interest rate swaps, cross currency swaps and forward contracts used by the
Group to reduce exposure to interest rate and currency risk.

Under IAS 39 all financial instruments are required to be recognised on the
balance sheet at fair value. If a derivative financial instrument is designated
as a "hedge", the movement in the fair value of the derivatives can be
recognised directly through reserves, which offsets the opposite movement in the
fair value of the hedged item, also in reserves. All other movements in the fair
value of financial instruments must be recognised as an income or expense in the
profit and loss account.

The Group has prepared documentation in line with the provisions of IAS 39 for
all hedging instruments and has established an ongoing procedure for testing the
effectiveness of these hedges which should permit the Group to adopt hedge
accounting for its financial instruments.

Deferred taxation

IAS 12 bases the calculation of the deferred tax assets and liabilities on the
difference between tax carrying values and balance sheet carrying values, rather
than the income statement approach required by FRS 19. As a result the scope of
IAS 12 is wider than that of FRS 19. The principal difference likely to affect
the Group is expected to be the deferred tax treatment of undistributed earnings
of subsidiaries, joint ventures and associates. The Group is also currently
assessing the tax effect of adjustments arising from the other differences
between UK GAAP and IFRS referred to above.


Independent review report by the auditors to mmO2 plc

Introduction

We have been instructed by the company to review the financial information which
comprise the profit and loss account, the balance sheet, the cash flow
statement, the statement of total recognised gains and losses and the related
notes. We have read the other information contained in the interim report and
considered whether it contains any apparent misstatements or material
inconsistencies with the financial information.

Directors' responsibilities

The interim report, including the financial information contained therein, is
the responsibility of, and has been approved by, the directors. The directors
are responsible for preparing the interim report in accordance with the Listing
Rules of the Financial Services Authority which require that the accounting
policies and presentation applied to the interim figures should be consistent
with those applied in preparing the preceding annual accounts except where any
changes, and the reasons for them, are disclosed.

Review work performed

We conducted our review in accordance with guidance contained in Bulletin 1999/4
issued by the Auditing Practices Board for use in the United Kingdom. A review
consists principally of making enquiries of group management and applying
analytical procedures to the financial information and underlying financial data
and, based thereon, assessing whether the accounting policies and presentation
have been consistently applied unless otherwise disclosed. A review excludes
audit procedures such as tests of controls and verification of assets,
liabilities and transactions. It is substantially less in scope than an audit
performed in accordance with United Kingdom Auditing Standards and therefore
provides a lower level of assurance than an audit. Accordingly we do not express
an audit opinion on the financial information. This report, including the
conclusion, has been prepared for and only for the company for the purpose of
the Listing Rules of the Financial Services Authority and for no other purpose.
We do not, in producing this report, accept or assume responsibility for any
other purpose or to any other person to whom this report is shown or into whose
hands it may come save where expressly agreed by our prior consent in writing.

Review conclusion

On the basis of our review we are not aware of any material modifications that
should be made to the financial information as presented for the six months
ended 30 September 2004.

PricewaterhouseCoopers LLP                                     16 November 2004
Chartered Accountants
London

The maintenance and integrity of the mmO2 plc web site is the responsibility of
the directors; the work carried out by the auditors does not involve
consideration of these matters and, accordingly, the auditors accept no
responsibility for any changes that may have occurred to the interim report
since it was initially presented on the web site.

Legislation in the United Kingdom governing the preparation and dissemination of
financial information may differ from legislation in other jurisdictions.



Appendix: Key Performance Indicators

1. Customer numbers



                                                               Net
             Customers   Customers Customers Customers   additions   Customers
                 at 30       at 31     at 31     at 30      during       at 30
             September    December     March      June      period   September
                  2003        2003      2004      2004                    2004
                 000's       000's     000's     000's       000's       000's
                                                        

- --------------------------------------------------------------------------------
O2 UK
Pre-pay          8,289       8,574     8,687     8,799         204       9,003
Post-pay         4,334       4,479     4,577     4,726         127       4,853
- --------------------------------------------------------------------------------
    Total       12,623      13,053    13,264    13,525         331      13,856
- --------------------------------------------------------------------------------

O2 Germany
Pre-pay          2,271       2,354     2,516     2,643         165       2,808
Post-pay         2,980       3,232     3,466     3,675         186       3,861
- --------------------------------------------------------------------------------
    Total        5,251       5,586     5,982     6,318         351       6,669
- --------------------------------------------------------------------------------

O2 Ireland
Pre-pay            901         992     1,010     1,007          25       1,032
Post-pay           373         378       381       388           5         393
- --------------------------------------------------------------------------------
    Total        1,274       1,370     1,391     1,395          30       1,425
- --------------------------------------------------------------------------------

Manx
Pre-pay             46          40        42        44           1          45
Post-pay            21          21        21        21           1          22
- --------------------------------------------------------------------------------
    Total           67          61        63        65           2          67
- --------------------------------------------------------------------------------

mmO2
Group
Pre-pay         11,507      11,960    12,255    12,493         395      12,888
Post-pay         7,708       8,110     8,445     8,810         319       9,129
- --------------------------------------------------------------------------------
    Total       19,215      20,070    20,700    21,303         714      22,017
- --------------------------------------------------------------------------------

Pre-pay
percentage        59.9%       59.6%     59.2%     58.6%       55.3%       58.5%

Post-pay
percentage        40.1%       40.4%     40.8%     41.4%       44.7%       41.5%
- --------------------------------------------------------------------------------






2. Average revenue per user(1) (ARPU) - GBP


3 months ended:              30              31       31       30           30
                      September        December    March     June    September
                           2003            2003     2004     2004         2004
                            GBP             GBP      GBP      GBP          GBP
                                                             
- --------------------------------------------------------------------------------
O2 UK (2)
12 month rolling
Pre-pay                     133             137      141      143          145
Post-pay                    508             512      525      537          541
Blended                     259             264      272      279          282

Monthly average
Pre-pay                      12              12       12       12           13
Post-pay                     45              43       45       46           46
Blended                      23              23       23       24           24
- --------------------------------------------------------------------------------

O2 Germany
12 month rolling
Pre-pay                      90              93       96       95           94
Post-pay                    363             373      375      368          366
Blended                     239             249      254      252          251

Monthly average
Pre-pay                       8               8        8        8            8
Post-pay                     32              31       30       30           31
Blended                      21              21       20       20           21
- --------------------------------------------------------------------------------

O2 Ireland
12 month rolling
Pre-pay                     236             245      248      247          244
Post-pay                    700             725      736      721          731
Blended                     372             385      388      381          380

Monthly average
Pre-pay                      22              21       20       20           21
Post-pay                     65              60       61       59           66
Blended                      34              33       32       31           33
- --------------------------------------------------------------------------------



(1) ARPU in all businesses includes revenue from inbound roaming.
(2) O2 UK ARPU includes Mobile Number Portability (MNP) revenue.

3. Data ARPU (blended 12 month rolling) - GBP



                                   31 March       30 June         30 September
                                       2004          2004                 2004
                                        GBP           GBP                  GBP
                                                                  

- --------------------------------------------------------------------------------
O2 UK                                    55            59                   62
O2 Germany                               49            51                   52
O2 Ireland                               75            81                   81
- --------------------------------------------------------------------------------



4. Average revenue per user(1) (ARPU) - Euro




3 months ended:               30              31       31       30          30
                       September        December    March     June   September
                            2003            2003     2004     2004        2004
                             EUR             EUR      EUR      EUR         EUR
                                                            

- --------------------------------------------------------------------------------

O2 Germany
12 month rolling
Pre-pay                      133             135      138      138         138
Post-pay                     538             539      540      537         540
Blended                      354             360      366      367         371

Monthly average
Pre-pay                       12              12       11       11          11
Post-pay                      46              45       44       45          46
Blended                       31              31       30       31          32
- --------------------------------------------------------------------------------

O2 Ireland
12 month rolling
Pre-pay                      349             355      357      361         360
Post-pay                   1,037           1,048    1,061    1,053       1,078
Blended                      551             556      559      556         560

Monthly average
Pre-pay                       31              31       29       30          31
Post-pay                      92              87       89       89          98
Blended                       49              47       45       46          49
- --------------------------------------------------------------------------------

Euro rates
Quarterly                 1.4310          1.4341   1.4718   1.5007      1.4880
Annually                  1.4802          1.4461   1.4405   1.4594      1.4736
- --------------------------------------------------------------------------------


(1) ARPU in all businesses includes revenue from inbound roaming.


5. Data ARPU (blended 12 month rolling) - Euro



                                   31 March       30 June         30 September
                                       2004          2004                 2004
                                        EUR           EUR                  EUR
                                                                  

- --------------------------------------------------------------------------------
O2 Germany                               71            74                   76
O2 Ireland                              110           118                  119
- --------------------------------------------------------------------------------




6. Voice minutes of use (mou) - blended monthly average(1)



12 months ended:        31 March   30 September     31 March      30 September
                            2003           2003         2004              2004
                                                             

- --------------------------------------------------------------------------------
O2 UK                        107            115          123               131
O2 Germany                   109            113          118               120
O2 Ireland                   188            192          197               203
- --------------------------------------------------------------------------------


(1) Includes total incoming and billable outgoing minutes.


7. Data as percentage of service revenues



3 months ended:             30             31         31       30           30
                     September        December     March     June    September
                          2003            2003      2004     2004         2004
                             %               %         %        %            %
                                                            

- --------------------------------------------------------------------------------
O2 UK                     19.4            21.2      22.3     21.3         23.0
O2 Germany                19.1            19.8      20.7     20.9         20.4
O2 Ireland                18.4            21.1      23.6     21.8         19.0
- --------------------------------------------------------------------------------
O2 Group                  19.2            20.9      22.0     21.2         21.9
- --------------------------------------------------------------------------------





12 months ended:            30              31        31       30           30
                     September        December     March     June    September
                          2003            2003      2004     2004         2004
                             %               %         %        %            %
                                                            
- --------------------------------------------------------------------------------
O2 Group                  19.0            19.8      20.1     20.9         21.5
- --------------------------------------------------------------------------------




8. SMS messages



3 months ended:             30              31        31        30           30
                     September        December     March      June     eptember
                          2003            2003      2004      2004         2004
                       million         million   million   million      million
                                                            
- --------------------------------------------------------------------------------

O2 UK                    1,861           2,106     2,309     2,348        2,470
O2 Germany                 423             468       507       532          556
O2 Ireland                 272             301       339       321          323
Manx                        21              16        19        19           10
- --------------------------------------------------------------------------------
O2 Group                 2,577           2,891     3,174     3,220        3,359
- --------------------------------------------------------------------------------



mmO2 Contacts:

Richard Poston                                   David Boyd
Director, Corporate Communications               Head of Investor Relations
mmO2 plc                                         mmO2 plc
richard.poston@o2.com                            david.boyd@o2.com
t: +44 (0)1753 628039                            t: +44 (0)1753 628230

David Nicholas                                   John Crosse
Communications Director                          Investor Relations Manager
mmO2 plc                                         mmO2 plc
david.nicholas@o2.com                            john.crosse@o2.com
t: +44 (0) 771 575 9176                          t: +44 (0)1753 628198

Simon Gordon
Press Relations Manager
mmO2 plc
simon.gordon@o2.com
t: +44 (0)771 007 0698

mmO2 press office: 01753 628402

   All mmO2 Group news releases can be accessed at our web site: www.mmo2.com

(end)




                              SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned, thereunto duly authorized.



                                                 mmO2 plc


Date: 17 November 2004                  By:___/s/ Robert Harwood___

                                           ROBERT HARWOOD
                                           Assistant Secretary