AN expanding engineering company is aiming to continue its growth after doubling the size of its factory.

GT Group, based in Peterlee, County Durham, has moved into a neighbouring plant on Whitehouse Business Park.

The company specialises in engine emission systems for global heavy-duty vehicle makers and earlier this year revealed £100m worth of work to increase the number of engine platforms it supplies from 320,000 this year to 500,000 in 2015.

Bosses say the 50,000sq ft factory expansion will help the firm build on an expected turnover increase of more than 35 per cent in 2014.

The company employs 350 workers and makes emission reduction control valves for diesel engines, including marine and construction vehicles, diggers and excavators.

It has five businesses designing and making products, including safety systems for transporting oil, gas and hazardous liquids, and special vehicle bodies for the mining industry.

Geoff Turnbull, GT Group chairman, who formed the company in the 1980s after starting his career as an engineering apprentice, said the expansion showed the North-East's manufacturing industry was strong.

He said: “We are entering an exciting new phase, which is one of the most significant in the company’s history, and will guarantee the longevity of the business for decades to come.

“Pundits keep writing off manufacturing as a dying industry but our mega expansion, our extremely healthy advance order book and the extent of our exports puts paid to this myth.

“Everyone at the company is passionate about manufacturing and the North-East and we are proud to be helping the region make its mark throughout the world.

“We export to 60 countries with overseas sales accounting for 80 per cent of our turnover, which grew by 25 per cent last year.”

The company also has bases in Consett and Newton Aycliffe, both in County Durham, and Sunderland, and was honoured in two business rankings earlier this year.

It was placed 74th in the Sunday Times International Track 200, which highlights Britain’s private companies with the fastest-growing overseas sales, and also named as the North-East company with the fastest-growing profits in the Sunday Times' PwC Profit Track 100.

Last year, the firm supplied heavy-duty trucks for US firm Ground Force Engineering, including a 13ft high vehicle, which is used to service bigger vehicles in quarries and mines with oil, water and fuel.