The manufacturing giant has seen turnover rise by almost 55% in the past year from £65m to £100m, taking on 260 new employees during the period.
A total of 75 of these new workers were employed and 19 existing jobs at the plant secured thanks to a £473,000 Let’s Grow Regional Growth Fund grant.
Business Durham, the economic development company for County Durham, worked with Thorn to access the funding which also bought new equipment for the Spennymoor plant.
The firm is a key supplier of LED lighting to local authorities across the UK, including Durham County Council, and to cities such as Oslo and Copenhagen.
Operations director, Steve Nixon, said: “We have seen continued growth right through 2015 and expect that we will still grow in 2016.
“Essentially the extra growth has come from three main areas. Firstly, taking over the work from our Swedish factory, secondly from the growth in our outdoor lighting, including the street lights, and thirdly from the continued move towards LED lighting which now accounts for the majority of our sales.”
Business Durham managing director, Simon Goon, added: “Thorn Lighting is an international manufacturing success story based in the heart of County Durham which we are proud to support.
“Its product innovation is in high demand, winning it major new contracts across the UK with the public sector and transforming the look and appeal of European capital cities with its intelligent LED lighting.”
Thorn Lighting is currently producing between 12,000 and 14,000 units at its plant everyday to service its increasing order book.