Omaha-based HDR employs more than 10,000 employees working out of 200 offices across the globe.

It had been looking to expand its presence in the UK after securing work for the both the Pirbright Institute in Surrey and Roslin Institute in Midlothian.

The two firms together will significantly increase the building engineering services offering, providing combined expertise equal to 1,200 staff. The business will trade as HDR | Hurley Palmer Flatt.

Eric Keen, HDR chairman, said that the acquisition would enable the expansion of HDR’s multidisciplinary building engineering services on a global scale.

Kenn said: “Hurley Palmer Flatt Group brings strong client relationships and specialised skill sets to HDR that, when combined with our capabilities, offer tremendous possibilities.

“By Combining our teams of professionals, we will develop a stronger building engineering practice globally.”

Paul Flatt joins the US engineer as managing director.

Hurley Palmer Flatt Group is headquartered in London and achieved revenue of nearly £40m last year, employing 240 staff.

The deal also includes recent acquisitions Andrew Reid, Bradbrook Consulting and Concentre Consulting.

Paul Flatt, managing director of Hurley Palmer Flatt Group, said: “HDR is the perfect strategic fit for the Hurley Palmer Flatt Group.

“The desire to have a meaningful impact on the organisation and to achieve strategic growth moving forward, makes HDR the ideal partner.”