Board Change

Costain Group PLC

("Costain" or the "Company")

Board Change

Further to the notification earlier today by Mohammed Abdulmohsin Al-Kharafi & Sons Co. W.L.L. ("Kharafi") of a disposal of major interest in shares, a disposal which takes their residual holding below the level at which they are entitled to a nominee directorship, Mr Ahmed Samy, a Non-Executive Director of Costain and the nominee of Kharafi on the Board, has notified the Board of his resignation as a Director of the Company with effect from 10 September 2015.

David Allvey, Chairman, commented:

"Ahmed has made a significant contribution to Costain since joining the Board in 2013 and we wish him well for the future."

11 September 2015