FORM 6-K

                      SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549


                            Report of Foreign Issuer


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


                           For the month of September, 2005


                             COLT TELECOM GROUP plc
                 (Translation of Registrant's Name into English)


                                 Beaufort House
                              15 St. Botolph Street
                                     London
                                    EC3A 7QN
                                     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 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- ________)



This Form 6-K shall be deemed to be incorporated by reference in the
Registrant's Registration Statement on Form F-3 (Reg. No.333-05972), in the
Registrant's Registration Statement on Form S-8 (Reg. No.333-8362)







COLT announces early redemption of 2% Senior Convertible Notes due 2006 (The
"Notes")

21  September  2005 - COLT  announced  today  that it has  given  notice  of the
redemption of all of the outstanding 2% Senior  Convertible  Notes due 2006. The
redemption will be at the principal  amount of the Notes  (EUR166,549,000)  plus
accreted  and accrued  interest and will be funded out of COLT's cash and liquid
resources.  The aggregate amount payable will be approximately GBP132.5 million.
The redemption will take place on 21 October 2005.

Commenting on the redemption,  Tony Bates,  Chief  Administrative  and Financial
Officer  said:  "The  early  redemption  of these  Notes  reflects  the  Board's
confidence in the financial  strength of COLT. We are firmly on track to be free
cash  flow  positive  for  the  second  half of the  year  and  thereafter  on a
sustainable annual basis."

The early redemption of these Notes will save  approximately  GBP1.25 million of
net interest  between now and the normal  maturity date of the Notes of 29 March
2006.

The early  redemption  of these Notes  brings the total  amount spent by COLT on
redeeming or buying back bonds to more than GBP560 million since October 2004.

About COLT

COLT is a leading European provider of business communications. COLT specialises
in providing data,  voice and managed  services to midsize and major  businesses
and wholesale  customers.  It has more than 50,000 customers across all industry
sectors.  COLT owns and operates a  13-country,  20,000km  network that includes
metropolitan  area  networks  in 32 major  European  cities  with  direct  fibre
connections into 10,000 buildings and 13 COLT data centres.

COLT Telecom  Group plc,  COLT's parent  company,  is listed on the London Stock
Exchange (CTM.L) and NASDAQ (COLT).  Information about COLT and its services can
be found at www.colt.net

For further information please contact:
Luke Glass
Tel +44 20 7390 3681
Email:luke.glass@colt.net

Gill Maclean
Tel: +44 20 7863 5314
Email: gill.maclean@colt.net




                                     SIGNATURES


Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this Current Report on Form-6K to be signed on its
behalf by undersigned, thereunto duly authorized.



Date: 21 September, 2005                            COLT Telecom Group plc



                                                     By: ___Jane Forrest___


                                                     Jane Forrest
                                                     Company Secretary