Geoffrey Turnbull runs GT Group, a Peterlee-based engineer which makes trucks and emission control systems for truck engines. Its new products have led to large contracts with Scania, Volvo and John Deere in recent months. In 2013 GT made £5.1m profit on £34m sales.
Latest turnover: £34m
Five-year rise in turnover: 143%
No. of employees: 266
Five-year rise in employment: 18%