Professor Sir. Ambrose Fleming comissioned the preparation of his prototype diode valve by the Edison Swan (later Mazda) factory at Ponders End near London in 1904. Professor Fleming was Technical Consultant to the Edison Swan Company at the time which may be why he did not use A C Cossor. . It was this close co-operation between University and Factory which resulted in the first radio valve in the world."
The Ediswan/Mazda company had a convoluted ownership path being in turn owned by AEI, BTH and Thorn. Valves were preduced in the Ediswan works but some were made in France through a tie up with Fivre.