Mullard Radio Valve Company Limited was founded in 1920 by Captain Stanley R. Mullard in Southfields, London. Captain Mullard had previously been involved with the design of thermionic valves for the Admiralty, and had also worked for the Z Electric Lamp Co. The company manufactured radio valves.

With the creation of the BBC in 1922 and the technical demands required, Mullard entered into a part share with the Dutch company, Philips in 1923 to aid with finances and meet these demands. In 1925, the company was renamed to Mullard Limited, a registered trade mark.