It said its focus in recent months on winning contracts in industries such as transport and mining, particularly in emerging markets, meant it should meet its own full-year expectations.
The company, which operates in more than 80 countries and built the Aquatics Centre for the London Olympics, posted a 12 per cent rise in underlying first-half pre-tax profit to £154m, lifted by a one-time gain from the sale of infrastructure investment assets.
Sales rose six per cent to £5.5bn.
“We do not anticipate any significant further reduction [in Britain] ... But in terms of recovery of volumes, it is difficult to see, in the very short term, where recovery is coming from,” deputy chief executive Andrew McNaughton said. The interim dividend was raised six per cent to 5.6p.