In the race to deliver highest profits, the civil engineering business came out top, contributing £18m to Bam’s UK construction operations.

Selective bidding at Nuttall helped to drive up margins from 1.8% to 2.5%.

BAM Construction also managed to weather the sharp downturn in building work by specialising in technically challenging projects. Pre-tax profits rose 20% to nearly £14m, with margins up to 1.5%.

Overall combined turnover for BAM Construct UK, BAM Nuttall and BAM PPP slid from £1.8bn in 2011 to £1.7bn last year. But pre-tax profits rose to £35m, as average margins improved in the tight market to 2.0%.

The UK combined forward order book is valued at £2.7bn.

Martin Rogers, director of Royal BAM Group, said: “BAM’s UK companies have continued to perform well in the challenging economic and business environment that continues to persist.

“The profitability of the UK companies improved in 2012 primarily as a result of careful market positioning, project selectivity and improved risk management and project execution.

Graham Cash, chief executive of BAM Construct UK, said: “We formed some significant new client relationships with customers who want high value construction and property services.

“We continue to innovate and to offer additional value to customers, for example, in the way we are developing building information modelling to help our customers manage their completed buildings more efficiently.”

BAM Nuttall’s chief executive, Steve Fox, said: “BAM Nuttall achieved a margin that exceeds most competitors and places us among the top performing businesses in the civil engineering market. Our order book remains strong, vindicating our selective approach to work winning.

“We continue to invest in developing our employees and supply chain  and continue to work with other BAM companies and in joint ventures, when appropriate, to leverage our business into a superior and sustainable position.’