Clarke has just signed a deal for the London Underground Bank station revamp adding to a set of big contract wins in the capital in the last six months.

The firm said it was now seeing greater client activity in the Capital but this had yet to work through to improved margins in the struggling sector.

This meant the building services firm only managed to break in its south region despite rising orders.

Reporting improved half-year group results, pre-tax profits edged up from £500,000 last time to around £800,000 in first half of 2013 on revenue surging 26% to £115m.

The south division covering London and representing £91m of total turnover failed to make a profit .

All group profit was generated in the North West region, with its smaller Scottish region posting a small loss.

Mark Lawrence, chief executive said: “The group has performed well, delivering a profitable half year, despite the continuing challenges in our markets.

“The forward order book has been maintained at £225m and we have improved the visibility of our workload, with some projects extending into 2015 and beyond.

He warned: “Competition remains fierce, yet we remain focused on choosing carefully which projects we tender for. Our cash position is solid and we ended the half year with an increased balance of £7.8m.

“Looking forward, there are signs of increased client activity especially in London, although this has yet to translate into improved margins.”