Preliminary figures for the year to September 30 2012 show pre-tax profits up to £8.4m from £2.6m last time as turnover fell slightly to £337.4m from £352.8m.

The energy,environmental and infrastructure operations at Renew now account for 60% of turnover and 90% of operating profit.

Profits were also up at the specialist building division where margins rose to 1.7% from 1.1% on a turnover of £123m.

Renew bosses have now set a turnover target of £500m by 2014 through organic growth and acquisitions.

Chief executive Brian May said: “The Group has made further progress in growing its Engineering Services business which focuses on supporting the maintenance and renewal of UK infrastructure increasing both revenue and operating profit.

“Specialist Building has increased its operating margin in the year and is concentrated on sustainable markets in the South.

“Our recent success in key framework appointments in Nuclear, Rail and Water together with our strong list of future opportunities demonstrates that the Group is pursuing the right strategy, evidenced by our growing forward order book and our record financial results.”