EXHIBIT 12.1

I, Steven P. Akin, certify that:

1.          I have reviewed this annual report on Form 20-F of COLT Telecom
            Group plc;

2.          Based on my knowledge, this annual report does not contain any
            untrue statement of a material fact or omit to state a material fact
            necessary to make the statements made, in light of the circumstances
            under which such statements were made, not misleading with respect
            to the period covered by this annual report;

3.          Based on my knowledge, the Financial Statements, and other financial
            information included in this report, fairly present in all material
            respects the financial condition, results of operations and cash
            flows of the registrant as of, and for, the periods presented in
            this annual report;

4.          The registrant's other certifying officers and I are responsible for
            establishing and maintaining disclosure controls and procedures (as
            defined in Exchange Act Rules 13a-14 and 15d-14) for the registrant
            and have:
            (a)         Designed such disclosure controls and procedures to
                        ensure that material information relating to the
                        registrant, including its consolidated subsidiaries, is
                        made known to us by others within those entities,
                        particularly during the period in which this annual
                        report is being prepared;
            (b)         Evaluated the effectiveness of the registrant's
                        disclosure controls and procedures and presented in this
                        report our conclusions about the effectiveness of the
                        disclosure controls and procedures, as of the end of the
                        period covered by this report based on such evaluation;
                        and
            (c)         Disclosed in this report any change in the registrant's
                        internal control over financial reporting that occurred
                        during the period covered by the annual report that has
                        materially affected, or is reasonably likely to
                        materially affect, the registrant's internal control
                        over financial reporting;

5.          The registrant's other certifying officers and I have disclosed,
            based on our most recent evaluation, to the registrant's auditors
            and the audit committee of registrant's board of directors (or
            persons performing the equivalent functions):
            (a)         All significant deficiencies and material weaknesses in
                        the design or operation of internal control over
                        financial reporting which are reasonably likely to
                        adversely affect the registrant's ability to record,
                        process, summarize and report financial information; and
            (b)         Any fraud, whether or not material, that involves
                        management or other employees who have a significant
                        role in the registrant's internal control over financial
                        reporting; and

6.          The registrant's other certifying officers and I have indicated in
            this annual report whether or not there were significant changes in
            internal controls or in other factors that could significantly
            affect internal controls subsequent to the date of our most recent
            evaluation, including any corrective actions with regard to
            significant deficiencies and material weaknesses.





/s/ Steven P. Akin
--------------------------------------
Steven P. Akin
President and Chief Executive Officer

Date: 30 April 2004