Results for the year to October 31 2011 show a 24% jump in turnover to £108m from £87m while operating profit also climbed to £420,000.

Keltbray has expanded rapidly into nuclear, rail and waste management and now employs around 800 staff.

Group chief executive and owner, Brendan Kerr, said: “Despite the prolonged, weak economic climate we are currently operating in, Keltbray is experiencing significant growth, and has started to reap the benefits of an assertive diversification strategy and extended geographical reach.

“From being a demolition and civils focused business in the South East; Keltbray is emerging into a turnkey specialist business, which provides integrated services to meet the needs of diverse and complex contracts in the areas of demolition and civil engineering, rail and environmental materials management nationwide.”

The company’s rail operations grew 67% in the year thanks to engineering, electrification, track, plant hire and signalling work.

Keltbray is now well placed to benefit from increased overhead line engineering work as part of the Government’s rail modernisation strategy and the firm secured a £46m contract earlier this year to provide power supply upgrades for Network Rail on the West Coast Main Line.

The core demolition and civils operations increased turnover by 20% during 2011 despite fierce competition and tight margins.

The company’s Doosan Keltbray Consortium joint venture led the way with several deplanting and asbestos removal contracts at Bradwell Power Station, as part of the five-year demolition framework contract set up by nuclear plant operator Magnox.

Finance Director John Keehan said: “We are in a great position to further bolster growth in the rail, nuclear and environmental sectors, which are amongst the few construction market segments that look strong in the short to medium term.

“We will also continue our strategy of building on our core strengths in demolition and civil engineering.”