SOURCE: COLT Telecom Group plc

October 24, 2005 09:56 ET

Colt Telecom Group PLC announces Blocklisting Six Monthly Return

London -- (MARKET WIRE) -- October 24, 2005 --

                        BLOCKLISTING SIX MONTHLY RETURN

Information provided on this form must be typed or printed electronically.

To: The FSA

Date: 24 October 2005

1. Name of applicant:

COLT Telecom Group plc

2. Name of scheme

2% Senior Convertible Notes due 2005 and 2006

3. Period of return:

From 23.04.05 To 24.10.05

4. Balance under scheme from previous return:

23,083,311

5. The amount by which the block scheme has been increased, if the scheme has been increased since the date of the last return

NIL

6. Number of securities issued/allotted under scheme during period:

NIL

7 Balance under scheme not yet issued/allotted at end of period

23,083,311

8. Number and class of securities originally listed and the date of admission

35,646,824 22.10.1999

9. Total number of securities in issue at the end of the period

1,512,344,666

Name of contact Michaella Henderson

Address of contact Beaufort House, 15 St Botolph Street, London, EC3A 7QN

Telephone number of contact 0207 947 1064

Signed by .........................................

Director/company secretary/suitably experienced employee/duly authorised officer, for and on behalf of

Name of applicant COLT Telecom Group plc

If you knowingly or recklessly give false or misleading information you may be liable to prosecution.

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