The acquisition also sees the launch of a new division – Costain Upstream – which will provide services across the life-cycle of upstream offshore oil and gas assets.

EPC employs 75 professional staff and is a field development and project management specialist providing client-side services to North Sea oil and gas companies.

EPC Offshore delivered revenue of £11.7m last year with a pre-tax profit of £1.1m.

The cost of the buyout could rise between £2m and £14.4m depending on financial performance over the next three years.

Costain Upstream will now combine the capabilities of ClerkMaxwell and EPC Offshore

The newly formed division will deliver engineering, capital projects and asset support services across four principal service lines; Field Development, Subsea Facilities, Topside Facilities, and Floating Systems, and employ 350 people.

Costain Upstream will be led by Keith Wallace, Chief Executive of EPC Offshore and will be based in Aberdeen with support units in Maidenhead, Teeside, Manchester and Abu Dhabi.

Costian has been keen to make more acquisitions following failed bids for Mouchel and May Gurney.

Andrew Wyllie, CEO of Costain, said: “We are delighted to welcome EPC Offshore to the Costain Group, in an acquisition which will accelerate our stated strategy of broadening our range of capabilities in response to the requirements of major blue chip customers.

“The formation of Costain Upstream will significantly enhance our position in this sector, and the acquisition of EPC Offshore will boost its growth, complementing the front-end engineering and operations capabilities we acquired with ClerkMaxwell two years ago.

“There is a sizeable addressable market for these highly complex services and we see further compelling opportunities to grow our oil and gas footprint both in the UK and internationally.”