================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

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

                                    FORM 6-K


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

                                January 12, 2005

                                Avecia Group plc
                                 ---------------
                 (Translation of registrant's name into English)


                                   P.O. Box 42
                                  Hexagon House
                              Blackley, Manchester
                                     M9 8ZS
                                     England
                                 ---------------
                    (Address of Principal Executive Offices)


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

                          Form 20-F [ X ] Form 40-F [ ]

(Indicate by check mark if the registrant is submitting the Form 6-K in paper as
               permitted by Regulation S-T Rule 101(b)(1): ____)

(Indicate by check mark if the registrant is submitting the Form 6-K in paper as
               permitted by Regulation S-T Rule 101(b)(7): ____)

(Indicate by check mark whether by furnishing the information contained in this
     Form, the registrant 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: Supplemental Offer to Purchase and Consent Solicitation
           Statement (to the Offer to Purchase Dated January 4, 2005) - Dated
           January 12, 2005

================================================================================



THIS SUPPLEMENTAL OFFER DOCUMENT IS IMPORTANT AND REQUIRES YOUR IMMEDIATE
ATTENTION. If you are in any doubt as to the contents of this supplemental offer
document or the action you should take, you are recommended to seek your own
financial advice immediately from your stockbroker, bank manager, solicitor,
accountant or other independent financial advisor authorized under the Financial
Services and Markets Act 2000, or from another appropriately authorized
independent financial advisor.


        SUPPLEMENTAL OFFER TO PURCHASE AND CONSENT SOLICITATION STATEMENT
                (TO THE OFFER TO PURCHASE DATED JANUARY 4, 2005)

                           Offer to Purchase for Cash
                                       by
                                AVECIA GROUP plc
                                     of its
                            11% Senior Notes Due 2009
                                       and
        Solicitation of Consents for Amendments to the Related Indenture


         This supplemental offer to purchase (the "Supplemental Offer to
Purchase") is supplemental to, and should be read in conjunction with, the offer
to purchase dated January 4, 2005 (the "Offer to Purchase") issued by Avecia
Group plc (the "Company") in relation to its offer to purchase for cash (the
"Tender Offer") its outstanding 11% Senior Notes due July 1, 2009 (the
"Securities") and the related consent solicitation.

         Terms defined in the Offer to Purchase have the same meaning in this
Supplemental Offer to Purchase.

         On January 10, 2005, the Company announced, inter alia, that it was
raising both the Maximum Offer Price, from US$990.00 to US$1,045.00 per
US$1,000.00 principal amount of the Securities, and the Minimum Offer Price,
from US$861.00 to US$980.00 per US$1,000.00 principal amount of the Securities,
in connection with its Tender Offer. The Consent Payment, in an amount equal to
US$10.00 per US$1,000.00 principal amount of Securities, remained unchanged.

         The increase in the Maximum Offer Price and the Minimum Offer Price
referred to in the proceeding paragraph results in changes to the Unaudited Pro
Forma Consolidated Financial Statements of the Company that were originally
published in the Offer to Purchase dated January 4, 2005. The previously
published Unaudited Pro Forma Consolidated Financial Statements had assumed that
the Available Tender Amount would be used to acquire Securities at a Clearing
Price of US$990.00 per US$1,000.00 principal amount of Securities, leaving
approximately US$81,000,000 aggregate principal amount of Securities outstanding
after the consummation of the Offer. The Company's revised Maximum Offer Price
and Minimum Offer Price results in the revised Unaudited Pro Forma Consolidated
Financial Statements contained in this Supplemental Offer to Purchase assuming
that the Available Tender Amount would be used to acquire Securities at a
Clearing Price of US$1,045.00 per US$1,000.00 principal amount of Securities,
leaving approximately US$104,900,000 aggregate principal amount of Securities
outstanding after the consummation of the Offer.




                                    Principal
                                    Amount           CUSIP                          ISIN
Title of Security                   Outstanding      Number                         Number         Common Code
- ---------------------------------   --------------   ----------------------------   ------------   -----------
                                                                                       
                                                     G9894BAA6 (Reg S Notes)        USG9894BAA64   -
11% Senior Notes due July 1, 2009   US$540,000,000   988788AA3 (144A Notes)         -              9875069
                                                     05354RAA9 (Registered Notes)   US05354RAA95   010588502




- --------------------------------------------------------------------------------
THE OFFER WILL EXPIRE AT 5:00 P.M., NEW YORK CITY TIME, ON FEBRUARY 1, 2005
UNLESS EXTENDED OR EARLIER TERMINATED (SUCH DATE AND TIME, AS THE SAME MAY BE
EXTENDED, THE "EXPIRATION TIME"). HOLDERS MUST TENDER THE SECURITIES (AS DEFINED
HEREIN) PRIOR TO THE EXPIRATION TIME TO BE ELIGIBLE TO RECEIVE THE TENDER OFFER
CONSIDERATION.

THE CONSENT PAYMENT DEADLINE (i.e., THE TIME BY WHICH HOLDERS MUST TENDER THE
SECURITIES IN ORDER TO BE ELIGIBLE TO RECEIVE THE TOTAL CONSIDERATION, A PORTION
OF WHICH WILL CONSTITUTE THE CONSENT PAYMENT WILL BE 5:00 P.M., NEW YORK CITY
TIME, ON JANUARY 18, 2005, UNLESS EXTENDED OR EARLIER TERMINATED.
- --------------------------------------------------------------------------------


         THIS SUPPLEMENTAL OFFER TO PURCHASE, THE OFFER TO PURCHASE AND THE
RELATED DOCUMENTS CONTAIN IMPORTANT INFORMATION WHICH SHOULD BE READ BEFORE A
DECISION IS MADE WITH RESPECT TO THE OFFER. THE OFFER IS SUBJECT TO A NUMBER OF
IMPORTANT CONDITIONS DESCRIBED IN THE OFFER TO PURCHASE.

         IF YOU HAVE RECENTLY SOLD OR OTHERWISE TRANSFERRED YOUR ENTIRE
HOLDING(S) OF SECURITIES, YOU SHOULD IMMEDIATELY FORWARD THIS SUPPLEMENTAL OFFER
TO PURCHASE AND THE OFFER TO PURCHASE TO THE PURCHASER OR TRANSFEREE, OR TO THE
BROKER, BANK OR OTHER AGENT THROUGH WHOM THE SALE OR TRANSFER WAS EFFECTED, FOR
TRANSMISSION TO THE PURCHASER OR TRANSFEREE.

         NEITHER THIS SUPPLEMENTAL OFFER TO PURCHASE, NOR THE OFFER TO PURCHASE,
HAVE BEEN FILED WITH OR REVIEWED BY ANY FEDERAL OR STATE SECURITIES COMMISSION
OR REGULATORY AUTHORITY OF ANY COUNTRY, NOR HAS ANY SUCH COMMISSION OR AUTHORITY
PASSED UPON THE ACCURACY OR ADEQUACY OF THE SUPPLEMENTAL OFFER TO PURCHASE OR
THE OFFER TO PURCHASE. ANY REPRESENTATION TO THE CONTRARY IS UNLAWFUL AND MAY BE
A CRIMINAL OFFENSE.

         The Dealer Manager for the Offer and the Solicitation Agent for the
Solicitation is:


                              Goldman, Sachs & Co.

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


       The date of this Supplemental Offer to Purchase is January 12, 2005




              UNAUDITED PRO FORMA CONSOLIDATED FINANCIAL STATEMENTS

         The accompanying unaudited pro-forma consolidated balance sheet of the
Company gives effect to the Transaction and the repayment of the term loan
facility and the revolving credit facility from the proceeds of the Transaction,
the disposal of the Company's interests in its former Additives business
(disposed of on January 31, 2004), Biocides business (disposed of on April 2,
2004) and Special Drug Mixtures business (disposed of on November 22, 2004), and
the consummation of the Offer (on the terms described below) in each case, as if
they had been consummated on September 30, 2004. The accompanying unaudited
pro-forma consolidated profit and loss accounts and statement of cash flows of
the Company gives effect to the Transaction and the repayment of the term loan
facility and the revolving credit facility from the proceeds of the Transaction,
the disposal of the Company's interests in its former Additives business,
Biocides business and Special Drug Mixtures business and the consummation of the
Offer (on the terms described below) in each case, as if they had been
consummated on October 1, 2003. The accompanying unaudited pro forma
consolidated financial statements assume that the Maximum Amount is used to make
the Consent Payment with respect to all outstanding Securities and that the
remaining amount, the Available Tender Amount, is used to acquire Securities at
a Clearing Price of US$1,045.00 per US$1,000.00 principal amount of Securities,
leaving approximately US$104,900,000 aggregate principal amount of Securities
outstanding after the consummation of the Offer. The pro forma financial
statements have been prepared in accordance with generally accepted accounting
standards in the United Kingdom. These accounting standards differ in certain
significant aspects from generally accepted accounting principles in the United
States.

         The pro forma information is presented for illustrative purposes only
and it is not necessarily indicative of the operating results or financial
position that would have occurred if the Transaction and the Tender Offer had
been consummated as presented in the accompanying unaudited pro-forma
consolidated financial statements, nor is it necessarily indicative of future
results of operations or the actual results of the Offer. The pro forma
adjustments and the assumptions on which they are based are described in the
accompanying notes to the Unaudited Pro Forma Consolidated Financial Statements.

         These pro forma consolidated financial statements should be read in
conjunction with the Company's historical financial statements and the related
notes thereto that have been incorporated herein by reference.


                                       2



                 Unaudited Pro Forma Consolidated Balance Sheet



                                                                             Pro Forma
                                       Historical          Pro Forma       September 30,
                                   September 30, 2004     Adjustments           2004         Footnotes
                                   ------------------   ---------------   ---------------   -----------
                                     (pound) million    (pound) million   (pound) million
                                                                                        
Fixed assets
Tangible fixed assets                         225.1              (54.1)             171.0           (1)
Intangible assets                             220.4             (161.7)              58.7           (2)


Investments in joint ventures:
Goodwill on joint ventures                      8.3                -                  8.3
Share of gross assets                          11.1                -                 11.1
Share of gross liabilities                     (1.5)               -                 (1.5)
                                     ---------------    ---------------    ---------------
                                               17.9                -                 17.9
                                     ---------------    ---------------    ---------------
Total fixed assets                            463.4             (215.8)             247.6

Current assets
Stocks                                         54.6              (14.5)              40.1           (1)
Debtors                                        93.7              (42.1)              51.6           (1)
Investments                                     8.3                -                  8.3
Cash at bank and in hand                        3.6                -                  3.6
                                     ---------------    ---------------    ---------------
Total current assets                          160.2              (56.6)             103.6
                                     ---------------    ---------------    ---------------

                                     ---------------    ---------------    ---------------
Total assets                                  623.6             (272.4)             351.2
                                     ---------------    ---------------    ---------------

Current liabilities
External loans due within less                  -                  -                  -
than one year
Other creditors                               (73.5)              31.3              (42.2)          (1)

                                     ---------------    ---------------    ---------------
Total current liabilities                     (73.5)              31.3              (42.2)
                                     ---------------    ---------------    ---------------

                                     ---------------    ---------------    ---------------
Net current assets                             86.7              (25.3)              61.4
                                     ---------------    ---------------    ---------------

External loans due within                    (362.0)             305.7              (56.3)          (3)
more than one year
Provisions for liabilities and                (21.2)               4.2              (17.0)          (1)
charges
Other creditors due within                     (8.3)               0.3               (8.0)
more than one year

                                     ---------------    ---------------    ---------------
Net assets excluding                          158.6               69.1              227.7
pension liability                    ---------------    ---------------    ---------------
Pension liability                             (96.2)              17.2              (79.0)          (1)

                                     ---------------    ---------------    ---------------
Net assets including                           62.4               86.3              148.7
pension liability                    ---------------    ---------------    ---------------

Shareholders equity                            22.3               86.3              108.6
Pay-in-kind 16% cumulative
redeemable                                     40.1                -                 40.1
     preference shares

                                     ---------------    ---------------    ---------------
Total                                          62.4               86.3              148.7
                                     ===============    ===============    ===============



                                       3



            Unaudited Pro Forma Consolidated Profit and Loss Accounts




                                         Historical                          Pro Forma
                                         12 months                           12 months
                                           ended                               ended
                                       September 30,       Pro Forma       September 30,
                                            2004          Adjustments           2004         Footnotes
                                      ---------------   ---------------   ---------------   -----------
                                      (pound) million   (pound) million   (pound) million

                                                                                        
Turnover, including share of joint             419.1            (234.4)            184.7            (4)
ventures
Less: share of joint ventures'                  (9.5)              -                (9.5)
turnover                              ---------------   ---------------   ---------------

Group turnover                                 409.6            (234.4)            175.2

Operating costs                               (429.4)            198.7            (230.7)           (4)
Exceptional operating costs                    (60.3)              -               (60.3)           (5)
Other operating income                           5.5              (1.3)              4.2            (6)
                                      ---------------   ---------------   ---------------

Group operating (loss)/profit                  (74.6)            (37.0)           (111.6)

Share of operating profit of joint               0.9               -                 0.9
ventures

Exceptional items                               89.5             (89.5)              -              (7)

                                      ---------------   ---------------   ---------------
Profit/(loss) on ordinary
activities before interest and                  15.8            (126.5)           (110.7)
taxation                              ---------------   ---------------   ---------------

Interest received                               34.3             (34.3)              -
Interest paid                                  (55.9)             49.3              (6.6)           (8)
Other finance costs                             (2.1)              -                (2.1)

                                      ---------------   ---------------   ---------------
Profit/(loss) on ordinary                       (7.9)           (111.5)           (119.4)
activities after taxation

Taxation on profit/(loss) on                    (0.7)              0.7               -              (9)
ordinary activities

                                      ---------------   ---------------   ---------------
Profit/(loss) on ordinary                       (8.6)           (110.8)           (119.4)
activities after taxation

Attributable to minority interests              (6.5)              -                (6.5)

                                      ---------------   ---------------   ---------------
Net profit/(loss) for the period               (15.1)           (110.8)           (125.9)
                                      ===============   ===============   ===============



                                       4



            Unaudited Pro Forma Consolidated Statement of Cash Flows



                                                Historical                          Pro Forma
                                                12 months                           12 months
                                                  ended                               ended
                                              September 30,       Pro Forma       September 30,
                                                   2004          Adjustments           2004         Footnotes
                                             ---------------   ---------------   ---------------   -----------
                                             (pound) million   (pound) million   (pound) million

                                                                                          
Operating (deficit)/profit before interest            (74.6)            (35.6)           (110.2)           (4)
Depreciation and amortization                          87.5              (8.0)             79.5       (4) (10)

Decrease/(increase) in inventories                     (0.8)              0.5              (0.3)           (4)
Decrease/(increase) in trade receivables              (13.5)              7.0              (6.5)           (4)
and other assets
(Decrease)/increase in accounts payable,                                                                   (4)
accrued expenses and                                   11.1              (6.1)              5.0
     trade provisions

Other cash and non-cash movements                       1.3               1.3               2.6            (4)

                                             ---------------   ---------------   ---------------
Net cash inflow from operating                         11.0             (40.9)            (29.9)
activities                                   ---------------   ---------------   ---------------

Returns on investment and servicing of
finance
Dividends received from associates                      3.1               -                 3.1
Interest received                                       1.3              (1.3)              -
Interest paid                                         (41.0)             34.5              (6.5)           (8)

                                             ---------------   ---------------   ---------------
Net cash (outflow) from returns on
investment and                                        (36.6)             33.2              (3.4)
     servicing of finance                    ---------------   ---------------   ---------------

Taxation                                                0.3               -                 0.3

Capital expenditure and financial
investments
Cash expenditure on fixed assets                      (26.5)              8.1             (18.4)           (4)
Disposals of fixed assets                               5.1              (5.0)              0.1           (11)

                                             ---------------   ---------------   ---------------
Net cash (outflow) from capital
expenditure and financial                             (21.4)              3.1             (18.3)
     investments                             ---------------   ---------------   ---------------

Acquisitions and disposals
Payments in respect of acquisitions                     -                 -                 -
Disposals of other investments                        171.8            (171.8)              -             (12)
Net cash disposed of                                   (0.2)              0.2               -
                                             ---------------   ---------------   ---------------
Net cash inflow from acquisitions and                 171.6            (171.6)              -
disposals                                    ---------------   ---------------   ---------------

Financing
Repayment of finance lease capital                     (0.9)              -                (0.9)
External loans repaid                                (126.2)            126.2               -             (12)
                                             ---------------   ---------------   ---------------
Net cash (outflow) from financing                    (127.1)            126.2              (0.9)
                                             ---------------   ---------------   ---------------

                                             ---------------   ---------------   ---------------
Net increase/(decrease) in cash                        (2.2)            (50.0)            (52.2)
                                             ===============   ===============   ===============



                                       5


FOOTNOTES
- ---------

         (1)  The pro forma adjustments eliminate balances relating to those
              businesses which have been disposed of during the 12-months ended
              September 30, 2004, namely the Additives business (disposed of on
              January 31, 2004), the Biocides business (disposed of on April 2,
              2004), Special Drug Mixtures (disposed of on November 22, 2004)
              and the NeoResins business (to be disposed of pursuant to the
              Transaction).

         (2)  The pro forma adjustment eliminates goodwill attributable to the
              NeoResins and Special Drug Mixtures businesses.

         (3)  The pro forma adjustment reflects the repayment of the existing
              term loan facility and revolving credit facility from the proceeds
              of the Transaction and the purchase of approximately $435,100,000
              of Securities (representing approximately 80.6% of the outstanding
              Securities) in connection with the Offer. The repayment amounts
              have been calculated using a September 30, 2004 exchange rate of
              1.81 for the purchase of the Securities pursuant to the Offer.

         (4)  The pro forma adjustment eliminates trading results relating to
              those businesses which have been disposed of during the 12-months
              ended September 30, 2004, namely the Additives business (disposed
              of on January 31, 2004), the Biocides business (disposed of on
              April 2, 2004), Special Drug Mixtures (disposed of on November 22,
              2004) and the NeoResins business (to be disposed of pursuant to
              the Transaction).

         (5)  Exceptional operating costs include a charge of (pound)42.3
              million for the impairment of goodwill, intangible assets and
              tangible assets and (pound)18.0 million for restructuring costs
              related to reductions in headcount.

         (6)  The pro forma adjustment eliminates the profit arising from the
              disposition of the Analytical Research Group on May 15, 2004 to
              Intertek Caleb Brett.

         (7)  The pro forma adjustment eliminates the profit on disposal of the
              Additives business (disposed of on January 31, 2004) and the
              Biocides businesses (disposed of on April 2, 2004).

         (8)  The pro forma adjustment adjusts interest expense to reflect the
              amount of interest that would have been charged to operations
              during the 12-months ended September 30, 2004, assuming that the
              term loan facility and revolving credit facility were repaid in
              full at the beginning of such period and assuming approximately
              US$104,900,000 of the Securities were outstanding for such period.

         (9)  The pro forma adjustment eliminates income tax expense for the
              12-months ended September 30, 2004 related to the operations of
              the NeoResins business.

         (10) Historical and pro forma depreciation and amortization for the
              12-months ended September 30, 2004 include a (pound)42.3 million
              charge for the impairment of goodwill, intangible assets and
              tangible assets.

         (11) Disposal of fixed assets primarily represents proceeds from the
              disposition of the Analytical Research Group on May 15, 2004 to
              Intertek Caleb Brett during the 12-months ended September 30,
              2004.

         (12) The pro forma adjustment eliminates the proceeds from the disposal
              of the Additives business (disposed of on January 31, 2004) and
              the Biocides businesses (disposed of on April 2, 2004), and the
              repayment of senior debt out of the proceeds of those
              dispositions.


                                       6



  The Information Agent and Tender Agent for the Offer and the Solicitation is:



                     Global Bondholder Services Corporation

                             65 Broadway - Suite 704
                               New York, NY 10006
                                       USA
                          Attention: Corporate Actions

                    Banks and Brokers call: +1 (212) 430 3774
                          Toll Free: +1 (866) 294 2200

                                  By Facsimile
                        (for Eligible Institutions only):
                                 (212) 430-3775


                                  Confirmation:
                                 (212) 430-3774


        By Mail:              By Overnight Courier:             By Hand:
65 Broadway - Suite 704      65 Broadway - Suite 704     65 Broadway - Suite 704
   New York, NY 10006          New York, NY 10006          New York, NY 10006
           USA                         USA                         USA


           The Luxembourg Agent for the Offer and the Solicitation is:

                        Kredietbank S.A. Luxembourgeoise
                               43 Boulevard Royal
                                     L-2955
                                   Luxembourg
                     Attention: Corporate Trust and Agencies
                           Telephone: +352 47 97 3935
                          By Facsimile: +352 4797 73951


Any questions or requests for assistance or for additional copies of this
Supplemental Offer to Purchase, the Offer to Purchase or related documents may
be directed to the Information Agent or the Luxembourg Agent at their respective
telephone numbers set forth above. A Holder may also contact the Dealer Manager,
Solicitation Agent and the Luxembourg Agent at their respective telephone
numbers set forth below or such Holder's broker, dealer, commercial bank, trust
company or other nominee for assistance concerning the Offer.



             The Dealer Manager for the Offer and Solicitation Agent
                            for the Solicitation is:


                              Goldman, Sachs & Co.
                           Liability Management Group
                           29th Floor, 85 Broad Street
                               New York, NY 10004
                                       USA
                          Toll Free: +1 (800) 828 3128
                           Collect: +1 (212) 357 3019
                     Attention: Credit Liability Management





                                   SIGNATURES

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.



                                               Avecia Group plc



Date: January 12, 2005                         By:    /s/ Derrick Nicholson
                                                      -----------------------
                                               Name:  Derrick Nicholson
                                               Title: Chief Financial Officer