COSTAIN GROUP PLC

("Costain" or the "Company")

Board changes

Costain is pleased to announce the appointment of Tony Quinlan as a non-executive director with effect from 1 February 2021. Tony will be a member of the Company's audit, remuneration and nomination committees.

Costain also announces that, after nine years' service on the Board, Jane Lodge, senior independent director and chair of the audit committee, will step down at the conclusion of the Company's 2021 annual general meeting expected to be held on 6 May 2021. It is intended Tony will succeed Jane as chair of the audit committee after the annual general meeting.

Tony, a chartered accountant, is currently a non-executive director of Hill & Smith Holdings PLC and Associated British Ports. He is also an advisor to Laird, having been chief executive officer and chief financial officer of Laird PLC when it was listed. Previously he was chief financial officer of Drax Group plc, held senior finance roles at Marks and Spencer plc and was deputy chairman and chairman of the audit committee for the Port of London Authority.

Dr Paul Golby CBE, chairman, said: "We are delighted that Tony is joining the Board. He is an experienced non-executive director and audit chair and also brings experience as a public company chief executive and FTSE 250 finance director. His experience in energy and technology will be an asset to Costain as the Group focuses on the decarbonisation and digital delivery of the UK's critical national infrastructure. We thank Jane for her considerable contribution to Costain since her appointment in 2012."

No further information is required to be disclosed under LR 9.6.13 R(2)-(6).

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