Appointment of Non Executive Director

COSTAIN GROUP PLC

("Costain" or the "Company")

JACQUELINE DE ROJAS APPOINTED TO BOARD

Costain has today appointed Jacqueline de Rojas as a non-executive director. The appointment is with effect from 20 November 2017. Jacqueline is a leader in the UK technology sector and an experienced non-executive director.

Dr Paul Golby CBE, chairman, said: "We are delighted that Jacqueline is joining the Board. She is a recognised and highly regarded technology leader in the UK and will bring an additional perspective to our Board as we continue to transform into the UK's leading smart infrastructure solutions company."

Jacqueline is currently a non-executive director at Rightmove plc, chair of the advisory board at the Digital Leaders Technology Group and is president of techUK.

Previously a non-executive director of Home Retail Group prior to the divestment of this group, she has held executive positions at global blue-chip software companies such as Citrix Systems, CA Technologies, McAfee and Novell.

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

17 November 2017