For the half year, pre-tax profit rose 56% to £33.8m from £21.6m before on revenue that increased 48% to £897.9m.

It said its building and infrastructure divisions have a strong spread of work across the public, regulated and private sectors while prospects for commercial building work ease.

However, the group said the housebuilding market remains challenging.

"We remain cautious on the outlook for the division, particularly if current market conditions persist throughout the spring selling season," it added.

"While the Board views the economic outlook with some caution, the group's financial strength and broad sector exposure will stand it in good stead during challenging times," said the group.