Half year results for the firm to September 30 2012 show pre-tax profits dipped slightly to £43.9m from £46.4m last time on turnover of £815.7m down from £842.9m.

The firm was boosted by its involvement in the 2012 Olympics as staff numbers increased by 3% to 17,756.

Uwe Krueger, chief executive officer, said: “The Group has delivered encouraging results in line with our expectations, with the sector and geographic spread of our business continuing to provide resilience in challenging markets.

“Implementation of our strategy continues and the outlook for the full year remains unchanged.

“We are pleased to be recruiting again and, in particular, are delighted to welcome over 500 graduates to the Group this autumn.

“We have been proud to be the official engineering design services provider to the London 2012 Olympic Games.  This project leaves an important regeneration legacy in London and is proving to be a valuable reference for both business development and staff recruitment.”