Profit before tax for the period came in at £10.1m compared with £8m in the same period last year on revenue that rose 9% to £467.5m.

The group said management actions taken last year, including raising £60m through a rights issue and increasing its banking and bonding facilities, has enabled it to secure larger contracts.

It has resulted in a record order book, up 25% to £2bn, from the year end level. The group said to facilitate further growth it has enhanced its banking and bonding facilities in the first half and its facilities now stand at £285m and been extended to 2011.

"We believe that, despite the current economic environment, our targeted blue-chip customers, in particular those in the public sector and regulated industries, will continue with their investment programmes," said the group.