Total Voting Rights

Costain notifies that as at 30 October 2026 its issued share capital comprised 260,930,913 ordinary shares of 1 pence each, with each share carrying one vote and no ordinary shares held in treasury; this share count should be used as the denominator for FCA Disclosure Guidance and Transparency Rule notification calculations. The company provides LEI 213800PKIJBZ2EDTKC88 and, in this administrative disclosure dated 2 November 2026, signals clarification of shareholder notification thresholds rather than material operational or financial change.