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SCHEDULE 13D

Amendment No. 6
COLT Telecom Group plc
Ordinary Shares
Cusip # G22944121


Cusip # G22944121
Item 1:	Reporting Person - FMR Corp.
Item 4:	AF
Item 6:	Delaware
Item 7:	893,479,066
Item 8:	None
Item 9:	893,479,066
Item 10:None
Item 11:893,479,066
Item 13:59.0%
Item 14:HC


Cusip # G22944121
Item 1:	Reporting Person - Edward C. Johnson 3d
Item 4:	AF
Item 6:	United States of America
Item 7:	None
Item 8:	None
Item 9:	893,479,066
Item 10:None
Item 11:893,479,066
Item 13:59.0%
Item 14:IN


Cusip # G22944121
Item 1:	Reporting Person - Abigail P. Johnson
Item 4:	AF
Item 6:	United States of America
Item 7:	None
Item 8:	None
Item 9:	893,479,066
Item 10:None
Item 11:893,479,066
Item 13:59.0%
Item 14:IN




Item 1.	Security and Issuer.

	This statement constitutes Amendment No. 6 to the Schedule 13D
originally filed with the Securities and Exchange Commission on
January 14, 2002 (the "Original 13D"), as amended by Amendment No. 1 filed
with the Commission on August 8, 2002, Amendment No. 2 filed with the
Commission on August 19, 2002, Amendment No. 3 filed with the Commission
on December 31, 2002, Amendment No. 4 filed with the Commission on
August 2, 2004, and Amendment No. 5 filed with the Commission on
August 18,2004, and relates to the ordinary shares, par value 2.5
pence per share (the "Ordinary Shares"), of COLT Telecom Group plc, a
corporation organized under the laws of England and Wales,
which has its principal executive offices at 15 Marylebone Road,
London, NW 15JD, United Kingdom (the "Company").

Item 2.	Identity and Background.

	The third paragraph of Item 2 is amended and restated
in its entirety as follows:

	Fidelity International Limited, a Bermuda joint stock company ("FIL"),
and various of FIL's foreign-based subsidiaries, provide investment advisory
and management services to a number of non-U.S. investment companies
and certain institutional investors.  FIL operates as an entity independent
of FMR and FMRCo.  FIL beneficially owns 111,449,420 Ordinary Shares
(representing 7.4% of the Ordinary Shares deemed outstanding on the date
hereof).  The business address and principal place of business of FIL is
Pembroke Hall, 42 Crow Lane, Hamilton, Bermuda.

	The last paragraph of Item 2 is amended and restated in its entirety as
follows:

	Within the past five years, none of the persons who were previously
named in Item 2 to this Schedule 13D, or listed on Schedule A or Schedule B
hereto, has been convicted in any criminal proceeding (excluding
traffic violations or similar misdemeanors) or has been a party to any civil
proceeding of a judicial or administrative body of competent jurisdiction as
a result of which any such person was or is subject to any judgment, decree
or final order enjoining future violations of, or prohibiting or mandating
activities subject to, federal or state securities laws
or finding any violations with respect to such laws.

Item 3.	Source and Amount of Funds or Other Consideration.

	Item 3 is supplemented as follows:

	During the past 60 days, Fidelity (as defined in Amendment No. 3)
purchased a total of 10,000,000 Ordinary Shares (the "Amd. 6 Subject
Shares") in the open market (with 100% of such purchases allocated to FIL)
for cash totaling approximately GBP 4,159,597, including a 0.5% stamp duty
and other taxes imposed on transactions of shares in companies organized
under the laws of England and Wales, and normal brokerage commissions.
The U.S. dollar equivalent of the total purchase price for the Amd. 6
Subject Shares, based on the foreign exchange rates reported in the
Federal Reserve Statistical Releases of Foreign Exchange Rates for the
various dates on which the Amd. 6 Subject Share purchases were settled,
was approximately $7,630,720. FIL used its own assets in making such
purchases and no part of the purchase price is represented by borrowed
funds.  The attached Schedule C sets forth the various purchase dates for
the Amd. 6 Subject Shares during the past 60 days, together with the
purchase prices in British pounds sterling and the respective U.S. dollar
equivalents based upon the exchange rates reported in the applicable
Federal Reserve Statistical Releases of Foreign Exchange Rates.



Item 4.	Purpose of Transaction.

	Item 4 is supplemented as follows:

	Fidelity purchased the Amd. 6 Subject Shares
in order to acquire an additional equity interest in the
Company. As of the date hereof, Fidelity is holding such securities solely
for investment and has no present plans or proposals with respect to any
material change in the Company's business or corporate structure or,
generally, any other action referred to in instructions (a) through (j)
of Item 4 of the form of Schedule 13D. Depending upon future evaluations
of the business prospects of the Company and upon other developments,
including, but not limited to,general economic and business conditions
and money market and stock market conditions, Fidelity may increase or
decrease its equity interest in the Company by acquiring additional
shares, or by disposing of all or a portion of the shares or
convertible notes.

Item 5.	Interest in Securities of Issuer.

	Item 5 is supplemented as follows:

	As of the date hereof, (a) FMR beneficially owned 893,479,066 Ordinary
Shares (representing 59.0% of the Ordinary Shares deemed outstanding on the
date hereof), (b) Edward C. Johnson 3d beneficially owned 893,479,066
Ordinary Shares (representing 59.0% of the Ordinary Shares deemed outstanding
on the date hereof), (c) Abigail P. Johnson beneficially owned 893,479,066
Ordinary Shares (representing 59.0% of the Ordinary Shares deemed
outstanding on the date hereof) and (iv) FIL beneficially owned 111,449,420
Ordinary Shares (representing 7.4% of the Ordinary Shares deemed outstanding
on the date hereof).

	As reported in Item 3 hereof, during the past 60 days FIL
purchased the 10,000,000 Amd. 6 Subject Shares in the open market for
cash at varying prices totaling GBP 4,159,597, including a 0.5% stamp duty
and other taxes imposed on transactions of shares in companies organized
under the laws of England and Wales, and normal brokerage commissions.
The U.S. dollar equivalent of the total purchase price for the Amd. 6
Subject Shares, based on the foreign exchange rates reported in
the Federal Reserve Statistical Releases of Foreign Exchange Rates for
the various dates on which the Amd. 6 Subject Shares purchased were settled,
was approximately $7,630,720.  As a result of such acquisitions, (i) FIL's
beneficial ownership increased to 111,449,420 Ordinary Shares (representing
7.4% of the Ordinary Shares deemed outstanding on the date hereof) and (ii)
the beneficial ownership of each of the Reporting Persons increased to
893,479,066 Ordinary Shares (representing 59.0% of the Ordinary Shares
deemed outstanding on the date hereof).

	Under U.K. law, FIL is not required to aggregate shares held
by FIL-advised index funds such as Fidelity Money Builder Index Fund with
shares held by entities of the FMR Concert Group for purposes of Rule 9
under the U.K. City Code on Takeovers and Mergers.

	Except as set forth herein, no transactions in the securities of the
Company were effected by the Reporting Persons or by FIL within the 60 days
prior to the date of this filing.

Item 6.	Contract, Arrangements, Understandings or Relationships With Respect
        to Securities of the Issuer.

	Item 6 is supplemented as follows:

	Except as otherwise set forth in the Original 13D, to the best
knowledge of the undersigned, there are no contracts, arrangements,
understandings or relationships (legal or otherwise) among or between
the undersigned and any other person with respect to any of the securities,
finder's fees, joint ventures, loan or option arrangements, puts or calls,
guarantees of profits, division of profits or loss, or the giving or
withholding of proxies.



Item 7.	Material to be Filed as Exhibits.

	Not applicable.


SCHEDULE A

Schedule A is amended and restated in its entirety as follows:

The name and present principal occupation or employment of each executive
officer and director of FMR are set forth below. The business address of each
person is 82 Devonshire Street, Boston, Massachusetts 02109, and the address
of the corporation or organization in which such employment is conducted is
the same as his business address. All of the persons listed below are U.S.
citizens.



                            POSITION WITH          PRINCIPAL
NAME                        FMR CORP.              OCCUPATION

Edward C. Johnson 3d        CEO, Director &        Chairman and Chief Executive
                            Chairman of the Board  Officer, Director, FMR Corp.

James C. Curvey             Director               Director, FMR Corp.

William L. Byrnes           Director               Director, FMR Corp.

Abigail P. Johnson          Director               Director, FMR Corp. &
                                                   President, Fidelity
                                                   Management & Research
                                                   Company

Laura B. Cronin		    Executive Vice	   Executive Vice
			    President &		   President &
			    Chief Financial	   Chief Financial
			    Officer		   Officer, FMR Corp.


Donald Haile                Fidelity Management    President, Fidelity
                            Committee Member       Investments Systems
                                                   Company

Stephen P. Jonas            Director 		   Director, Executive
						   Vice President of
						   Enterprise Operations
						   and Risk Services, FMR
						   Corp.

Joseph LoRusso		    Fidelity Management	   President, Fidelity
			    Committee Member       Financial Intermediary
						   Services

Ellyn A. McColgan           Fidelity Management    President, Fidelity
                            Committee Member       Brokerage Company

D. Ellen Wilson             Executive Vice         Executive Vice President,
                            President, Human       Human Resources,
			    Resources              FMR Corp.

Robert L. Reynolds          Director, Vice 	   Director, Vice
			    Chairman &             Chairman & Chief
                            Chief Operating        Operating Officer,
                            Officer                FMR Corp.

Peter J. Smail              Fidelity Management    President, Fidelity
                            Committee Member       Employer Services Company



SCHEDULE B

	Schedule B is amended and restated in its entirety as follows:

	The name and present principal occupation or employment of each
executive officer and director of Fidelity International Limited are set
forth below.  The business address of (a) Messrs. Johnson, Byrnes and Walsh
is FMR Corp., 82 Devonshire Street, Boston, MA 02109, (b) Messrs.
Bateman and Haslam is Oakhill House, 130 Tonbridge Road,
Hildenborough, Kent TN11 9DZ, England, (c) Messrs. Saul, Moreno, Stewart
Mutch, Seed, and Ms. Powell is Pembroke Hall, 42 Crow Lane, Pembroke,
HM19, Bermuda, (d) Mr. Goodin is Shiroyama JT, Mori Building, 19th
floor, Minato-Ku 105, Japan, (e) Mr. Boyle is Hardwicke House, Upper
Hatch Street, Dublin 2, Ireland and (f) Mr.Dennison is 483 Bay Street,
Toronto, Ontario, Canada M5G 2NZ.  The address of each corporation or
organization in which such principal occupation or employment is conducted
is the same as the business address set forth above. Messrs. Johnson,
Byrnes, Moreno and Walsh are United States citizens; Messrs. Bateman,
Haslam, Seed, and Boyle are British citizens; Messrs.Saul,
Mutch and Stewart are dual Bermudan and British citizens; Mr. Goodin
is a New Zealand citizen and Mr.Denison and Ms.Powell are Canadian
citizens.



NAME                         POSITION WITH             PRINCIPAL OCCUPATION
                             FIDELITY INTERNATIONAL
                             LIMITED

Edward C. Johnson 3d         Director &                Chairman and Chief
                             Chairman of the Board     Executive Officer,
                                                       Director, FMR Corp.

Barry R.J. Bateman	    Director & Vice-Chairman	Vice-Chairman, Fidelity
							International Limited



William L. Byrnes            Director                  Director, FMR Corp.


Glen R. Moreno               Director                  Non-Executive Director,
                                                       Fidelity International
                                                       Limited

David J. Saul                Director                  Non-Executive Director,
                                                       Fidelity International
						       Limited

Frank Mutch                  Director                  Non-Executive Director,
                                                       Fidelity International
						       Limited

David Denison                Director                  President, Fidelity
                                                       Investments Canada
                                                       Limited

Richard Walsh                Director                  Non-Executive Director,
                                                       Fidelity International
                                                       Limited

Brett Goodin                 Director                  President, Asia-Pacific
                                                       business

Simon Haslam                 Director and Chief        Chief Administrative
                             Administrative Officer    Officer, Fidelity
                                                       International Limited

Graham R. Seed               Secretary                 Secretary, Fideltiy
                                                       International Limited

Robert Stewart               Director		       Non-Executive Director,
						       Fidelity International
						       Limited

Jon Boyle                    Director of Treasury      Director of Treasury,
                                                       Fidelity International
                                                       Limited

Rosalie Powell               Assistant Company         Assistant Company
                             Secretary                 Secretary, Fidelity
                                                       International Limited




SCHEDULE C

Schedule C is amended as follows:

During the past 60 days, Fidelity International Limited has purchased
Ordinary Shares for cash in the open market as set forth below.


DATE            NUMBER                PRICE PER             DOLLAR EQUIVALENT
                OF ORDINARY SHARES    ORDINARY SHARE(GBP)   PRICE PER
                                                            ORDINARY SHARE
10/21/04            2,725,000              GBP 0.42                $0.76
10/22/04            860,000                GBP 0.41                $0.75
10/25/04            2,000,000              GBP 0.40                $0.73
10/26/04	    550,000		   GBP 0.40		   $0.74
10/27/04	    800,000		   GBP 0.42		   $0.76*
10/28/04	    1,000,000		   GBP 0.43		   $0.78*
10/29/04	    2,065,000		   GBP 0.43		   $0.80*
___________________
* Based on the October 29, 2004 exchange rate.



SIGNATURE

	After reasonable inquiry and to the best of my knowledge and
belief, I certify that the information set forth in this statement is
true, complete and correct.

						  FMR Corp.



DATE:	November 1, 2004
						   By: /s/ Eric D. Roiter
						   Eric D. Roiter
						   Senior V.P. & Deputy
						   General Counsel - Fidelity
						   Management and Research
                                                   Company. Duly authorized
                                                   under Power of Attorney
                                                   dated December 30, 1997, by
                                                   and on behalf of FMR Corp.
                                                   and its direct and indirect
                                                   subsidiaries

Attachment



Attachment		Attachment Description
Number

1	Power of Attorney dated December 30, 1997**


**Filed with the original Schedule 13D dated January 14, 2002, and incorporated
by reference herein.