Mullard Radio Valve Co
From Graces Guide
Radio valve manufacturers, of Mitcham
1920 The Mullard Radio Valve Co Ltd. of Southfields, London, was founded by Captain Stanley R. Mullard,, who had previously designed valves for the Admiralty before becoming managing director of the Z Electric Lamp Co.
Mullard's new company had significant financial backing from the Radio Communication Co. Ltd who were interested in having a competitor to the Marconi monopoly in marine radio.
Mullard set up new manufacturing facilities at Hammersmith. His first products were variations of the 'R' type valve as well as transmitting valves.
1922 Broadcasting began in Britain which further fuelled the growth of the business.
Marconi group brought a suit against Mullards, alleging infringement of their patents. Mullard fought the case as far as the House of Lords, with judgment given in his favour at every stage. Against Marconi's opinion that the design of valve published in a German book would not work, Mullard made 20 overnight and demonstrated them in a receiver in Court the next day. The small company would probably not have survived without the support of their backers and of the Admiralty who had adopted Mullards valves as standard.
1923 The business grew and in 1923 transferred to Balham in South London.
1924 The need for additional capital was such that Mullard sought external finance as well as additional technical resources, which led to Mullard selling half of his shares to the N. V. Philips company of the Netherlands. This partnership with Philips also helped to meet the technical demands of the newly formed British Broadcasting Company (later Corporation) or BBC. The valves produced in this period were named with the prefix PM, for Philips-Mullard, beginning with the PM3 and PM4 in 1926.
1927 Philips acquired the remainder of the shares in the company.
1929 Stanley Mullard resigned as managing director
For the later activities of the company see Mullard.
1961 Manufacturers of X-Ray, electron and cathode-ray tubes, semi-conductors, magnetic materials electronic components and equipment and fine wire. 
Sources of Information
- Mullard History