Dollis Hill in northwest London was the home of the Post Office Research Station from the 1920’s to the 1970’s. The station was dedicated mainly to research in telecommunications and the teams at Dollis Hill played a leading role in a number of key advances in the field.
In 1914, the Postmaster General agreed that the Post Office needed improved facilities for research and that a permanent Engineering Research Station should be established. Five years later, the Treasury agreed to buy the Dollis Hill site. Initially, staff worked in wooden ex-army huts until the permanent buildings had been completed. The main research building opened in 1923.
The 1930’s were years of rapid developments in the telecommunications field and the various research teams at Dollis Hill made many important contributions. In 1936, the Speaking Clock - known to London users as TIM - was designed and constructed there by Dr E.A. Speight. The Dollis Hill teams were also responsible for the development of the Trans-Atlantic telephone cable and for providing the links for outside television broadcasts, such as the first broadcast of the Remembrance Day service in 1937.
One of the research station’s more unusual experiments involved a headless postman figure, which was used to test what types of waterproof material lasted under the constant friction of the postman’s bag rubbing against the regulation uniform.
Dollis Hill Research Station also had two important secrets during the war. One was the reserve Cabinet War Rooms hidden in a bunker underneath the building, equipped to be used if the main Cabinet War Rooms in central London were bombed. The other was the 2,000-valve “Colossus” computer that helped to break the German Enigma radio code, which was designed and built at the research station.
In 1943, T. H. “Tommy” Flowers was asked to design a machine that could be used to decode German radio signals. The decoders working at Bletchley Park rejected Tommy Flower’s proposal for the Colossus computers, but the project was later authorised by the Director at Dollis Hill. Working 90 hours a week with fellow engineers Sidney Broadhurst and William Chandler, Flowers had the first Colossus machine ready by December 1943. Construction and testing took at place at the research station, before the Colossus was reassembled at Bletchley Park.
As the 1960’s progressed, it became clear that the research station was no longer big enough. The Dollis Hill site was abandoned and a new centre was built in Suffolk. The Post Office finally left Dollis Hill in 1976. In the 1990’s the building received a fresh lease of life when it was converted into flats.
