EXHIBIT 12.5

                            CERTIFICATION PURSUANT TO
                 18 U.S.C. SECTION 1350, AS ADOPTED PURSUANT TO
                  SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

            In connection  with the filing of the Annual Report on Form 20-F for
the fiscal year ended December 31, 2002 (the "Report") by COLT Telecom Group plc
(the "Company"), the undersigned, as the Chief Financial Officer of the Company,
hereby certifies  pursuant to 18 U.S.C. ss. 1350, as adopted pursuant to ss. 906
of the Sarbanes-Oxley Act of 2002, that, to my knowledge:

o     the Report  fully  complies  with the  requirements  of  Section  13(a) or
      Section 15(d) of the Securities Exchange Act of 1934; and

o     the information  contained in the Report fairly presents,  in all material
      respects,  the  financial  condition  and  results  of  operations  of the
      Company.



                                           /s/ Marina M. Wyatt
                                           Marina M. Wyatt
                                           Chief Financial Officer





A signed  original of this  written  statement  required by Section 906 has been
provided to the Company and will be retained by the Company and furnished to the
Securities and Exchange Commission or its staff upon request.