British Thomson-Houston was formed in 1896, financed with capital from American Thomson-Houston (which was founded in 1879). Primarily created to act as an agent for its American partner, BTH quickly became a company in its own right after acquiring patents and manufacturing rights. (American Thomson-Houston later became part of General Electric, hence the similarity of their logos).

Initially BTH wanted to become a power generator, lobbying parliament to provide electricity to the north east of England. This failed, so BTH went on to produce steam turbines, motors and engines from their newly built Rugby factory.

In 1911, BTH obtained the GE patents for tungsten filaments and the Mazda trademark. Bulbs and lanterns were therefore sold under the Mazda trade name.

After the First World War, BTH expanded considerably, moving into radio and domestic appliances, whilst the lamp business was the company’s primary strength.

A merger with GEC and English Electric was suggested in 1926 (prompted by US firm Westinghouse who held the majority of shares in English Electric.) This backfired - GEC were suspicious of the US involvement and pulled out. However BTH and Metropolitan Vickers were joined in 1928, being jointly held by the newly formed financial holding company Associated Electrical Industries.

During the Second World War, BTH moved into aircraft production, constructing the jet engine a few years before hostilities broke out (using centrifugal compressors developed by Sir Frank Whittle). BTH did not continue research into the jet engine, claiming that it could not divert resources away from their electrical business.

Another war time development was BTH’s significant part in the development of radar.

However, all was not well despite BTH’s continued success with turbines and power generation after the Second World War. The company often fought against Metrovick, a luxury no longer permitted after poor financial performance. Therefore, to regenerate the parent company, re-establish the company’s dominance in electrical market, and to reorganize the internal structures, the names of BTH and Metrovick were abolished on January 1st 1960 – the product lines being merged and consolidated under the AEI banner.