Denman Products Limited and Denman Tools Limited were located at Tewin Road in Welwyn Garden City. They were established around the time of the second world war by John Denman Dean of Cushendall, County Antrim, Northern Ireland. He patented the original Denman brush in 1938 but secondment to the American government for the duration of WWII interrupted any plans to commercialise the product. The Denman brushes use the inventor’s middle name and continues as a brand known worldwide in hairdressing circles.