HOLMES MASTER ISSUER PLC

(a public company incorporated with limited liability in England and Wales with registered number 05953811)

Publication of Supplemental Prospectus

The following prospectus supplement has been approved by the UK Financial Conduct Authority and is available for viewing:

Supplement dated 22 May 2026 (the Supplement) to the prospectus dated 11 May 2026 relating to the Residential Mortgage-Backed Note Issuance Programme of Holmes Master Issuer plc (the Prospectus).

The Supplement is available for viewing by clicking on or pasting the following URL into the address bar of your browser:

https://data.fca.org.uk/artefacts/NSM/DirectUpload/NI-000145457/NI-000145457.pdf

A copy of the Supplement has been submitted to the National Storage Mechanism and will shortly be available for inspection at: https://data.fca.org.uk/#/nsm/nationalstoragemechanism

The Supplement will also be available for viewing at:

https://www.santander.co.uk/about-santander/investor-relations/holmes-master-trust

For further information, please contact:

Funding, Asset Rotation and Investor Relations
Santander UK plc
2 Triton Square
Regent's Place
London NW1 3AN

Email: [email protected]

DISCLAIMER - INTENDED ADDRESSEES

Please note that the information contained in the Supplement (and the Prospectus to which it relates) may be addressed to and/or targeted at persons who are residents of particular countries (as specified in the Supplement and the Prospectus) only and is not intended for use and should not be relied upon by any person outside these countries and/or to whom the offer contained in the Supplement and the Prospectus is not addressed. Prior to relying on the information contained in the Supplement and the Prospectus, you must ascertain from the Supplement and the Prospectus whether or not you are part of the intended addressees of the information contained therein.

Your right to access this service is conditional upon complying with the above requirement.

The securities described herein have not been, and will not be, registered under the U.S. Securities Act of 1933, as amended (the "Securities Act"), or under any relevant securities laws of any state of the United States of America, and may not be offered or sold in, the United States of America, or to, or for the benefit of, U.S. persons (as defined in Regulation S of the Securities Act) except to persons that are qualified institutional buyers within the meaning of Rule 144A under the Securities Act, or in transactions that occur outside the United States to persons other than U.S. persons in accordance with Regulation S, unless the securities are registered under the Securities Act or an exemption from the registration requirements of the Securities Act is available.