The UK’s biggest building firm cheered the growing momentum of its US arm after stronger than expected first-half profits.

Balfour Beatty is weathering the slump with a £12.5 billion order book bolstered by several major contracts in the US, which now accounts for 30 per cent of group revenues.

Despite weaker regional building markets at home, it also made “good progress” on several road-building schemes, including the A46 Newark to Widmerpool deal brought forward under Government stimulus plans.

Shares jumped eight per cent after the firm’s pre-tax profits rose 14 per cent to £108 million, at the top end of City hopes.

Balfour first entered the US market in the 1980s but its 2007 acquisition of housebuilder Centex’s construction arm gave a major spurt to growth.

The division, a major player in military housing, landed contracts in Texas, North Carolina, and California from clients including the US Army Corps of Engineers.

The wins offset the impact of a 18 per cent fall in orders in its building division since the end of 2008, due to currency impacts and the downturn in commercial building markets.

Chief executive Ian Tyler said: “We have made good progress in the US, based on the principles which have made our UK business so successful.”