Director Declaration - External Appointment

                                           10-11 CHARTERHOUSE SQUARE, LONDON EC1M 6EE

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3 March 2025

DIRECTOR DECLARATION - EXTERNAL APPOINTMENT

Diploma PLC (the "Company"), the international value-add distribution group, has been notified that Ian El-Mokadem, a Non-Executive Director, will be appointed to the Board, and Nomination, Audit and Compliance Committees, of United Utilities Group PLC as a Non-Executive Director with effect from 1 June 2025.

This announcement is made pursuant to LR 6.4.9 of the Listing Rules.

J Morrison

Group General Counsel & Company Secretary

Diploma PLC

For further information, please contact:

Further information on Diploma PLC can be found at www.diplomaplc.com

LEI: 2138008OGI7VYG8FGR19