EXHIBIT 12.1 CONSENT OF PriceWaterhouseCoopers LLP Consent of Independent Accountants We hereby consent to the incorporation by reference in the Registration Statement on Form F-3 (Registration No. 333-05972) of COLT Telecom Group plc and in the Registration Statement on Form S-8 (Registration No. 333-8362) of COLT Telecom Group plc, of our report dated 26 February 2003 relating to the consolidated financial statements and the financial statement schedules, which is incorporated in this Annual Report on Form 20-F. /s/ PricewaterhouseCoopers LLP PricewaterhouseCoopers LLP Chartered Accountants and Registered Auditors London England 27 June 2003