A C Cossor Ltd. Cossor is reputed to have made some experimental valves for Fleming, and was an important manufacturer of valves during WWI. The company manufactured a full range of receiving valves at its factory in Highbury. Although it is not widely known, M-OV held a substantial shareholding in Cossor, which it purchased from GEC on 30 April 1927 for the sum of £94,766.8s. Following the purchase, an M-OV director was appointed to the Cossor Board, which meant that regular reports of Cossor activities were available to M-OV. Towards the end of 1927, Cossor signed a licence agreement with M-OV for the use of their valve patents. Cossor became a public company in 1938, a year after the death of its Managing Director, W R Bullimore - a man who played an important part in the growth and success of the company. After 1945, the company reorganised its valve business and formed a new subsidiary company, Electronic Tubes Ltd. EMI acquired a controlling interest in the company in 1949.