Davis Langdon senior partner Rob Smith said: “Now, more than ever before, our clients are looking for integrated solutions and access to global knowledge.

“In partnership with Aecom, Davis Langdon will be well-positioned to deliver our front- end cost and project management, and consultancy services as part of a complete end-to-end offer.

“This will allow us to better serve our global customers while presenting new long-term growth opportunities for our employees.

“We look forward to further penetrating the markets we share with Aecom and leveraging their global platform to enter new growth markets.”

Davis Langdon employs around 2,500 people worldwide and has an annual turnover of around £300m.

Aecom describes itself as “a global provider of professional technical and management support services to a broad range of markets, including transportation, facilities, environmental, energy, water and government.”

The firm currently has approximately 45,000 employees around the world with a turnover of £3.8bn.

Aecom has been pursuing targets in the UK market since 2000 when it bought consultant Guy Maunsell International.

The Davis Langdon deal has intensified concerns in the sector that giant consultants will snap-up an even larger share of work.

One consultant said: “This will further reduce the opportunity for smaller consultancies to win major projects.

“I suppose the corporate approach is inevitable given the significant savings associated with a single brand approach and the obvious preference by clients for appointing huge organisations to deliver projects.”