COSTAIN PLC

5 MAY 2022

TRADING IN LINE WITH MARKET EXPECTATIONS

Costain Group PLC is today holding its Annual General Meeting (AGM).

Alongside our AGM we are confirming that we are trading in line with market expectations. Whilst we are mindful of the macro-economic backdrop, particularly regarding cost inflation, we continue to expect to deliver further progress in 2022 and remain confident in the Group's strategy and longer-term prospects.

The AGM will be broadcast live at 3pm and this can be accessed on our website: www.costain.com/agm.

As part of the AGM presentation, we will provide a short business update drawing on the information published on 9 March 2022. There is no new material information.

As previously announced, Fiona MacAulay will take over as chair of the Remuneration Committee at the conclusion of the AGM.

ENQUIRIES

Investors and analysts

Louise Bryant, Costain                                                +44 7813 210 809

Financial media - Headland                                     costain@headlandconsultancy.com

Andy Rivett-Carnac                                                    +44 7968 997 365