Board Changes

Costain Group PLC

("Costain" or "the Group")

Board Changes

The Costain Group PLC Board is pleased to announce the appointment of Jane Lodge as a Non-Executive Director with effect from 1 August 2012. Jane will Chair the Audit Committee from 31 October 2012, replacing James Morley who will become the Senior Independent Director. James will succeed John Bryant, who will retire at the end of 2012 after nearly 11 years as a Board member.

Jane spent 35 years at Deloitte LLP (UK), 25 of which as an audit partner advising global companies in the manufacturing and infrastructure sectors. Her Deloitte career also included leadership roles as the senior partner of the Midlands offices and as the UK manufacturing practice industry leader where she was responsible for the development and implementation of marketing strategy for that practice sector.

Jane is also a Non-Executive Director and Chair of the Audit Committee at Devro Plc. No further information is required to be disclosed under LR 9.6.13 R(1)-(6).

David Allvey, Costain Group Chairman, said:

"Jane's appointment will add much valuable experience to our Board as we build on the successful transformation of the Group into a leading engineering solutions provider.

On behalf of Board colleagues and myself, albeit ahead of his retirement, I would like to record our sincere thanks to John Bryant for his ongoing commitment and significant contribution to the Company."

16 July 2012