Costain increased its forward order book by 19% to £1.9bn in the first three months of 2008.

In a first-quarter trading update, it said it expected to perform in line with expectations as it continued to focus on blue chip clients.

A statement said: “Work continues on improving margin performance following the remedial actions put in place during 2007.”

The consensus forecast for 2008 is pre-tax profit of £22.4m on turnover of £784.4m.