The firm said margins across its nationwide business were still under pressure as firms traditionally active in the public sector turned to bidding office jobs.

Despite very tough trading half-year profits have held up well. In the first six months of 2010, T Clarke returned a pre-tax profit of £3.2m compared to £4m for the same period last year.

Turnover slipped 8% to £85.7m with underlying operating margin down from 5.5% to 4.5%.

Mark Lawrence, chief executive, said: “The group has maintained its market share in the period and has secured some of the most significant projects available despite a continuing tough and challenging environment.”

He added that tendering activity was high across the group and it was particularly encouraging that major commercial schemes in London were being brought to market for construction during 2011, for completion in 2013.

The firm’s forward order book improved to £220m, compared to £170m last year, but margins remained under pressure.

Lawrence said T Clarke was not over dependent on Government-funded schemes, but faced increased competition from contractors that previously serviced the public sector.

Net cash and bank deposits remained positive at £7.4m, down from £23.3m at the end of last year.

Across the group, the south east business traded well. After taking account of restructuring costs, operating profit margin was up from 4.7% to 6.6% in the first half.

In Scotland, trading proved tougher with T Clarke posting an operating loss of £1.1m.