http://en.wikipedia.org/wiki/Dollis_Hill
Quote
The engineer Tommy Flowers joined the telecommunications branch of the General Post Office in 1926. While working at the research station in Dollis Hill in the 1930s, he began to explore the possible use of electronics for the telephone exchange. Experimental equipment that he built in 1934 went into operation 5 years later, converting a portion of the telephone exchange network into an electronic data processing system, using thousands of vacuum tubes.[38]
Quote
Dollis Hill played a part in the Second World War as the code-breaking computer used at Bletchley Park was built at the Post Office Research Station in Dollis Hill and the rarely used alternative Cabinet War Room bunker for Winston Churchill's government was dug underground here.
sorry 
So many guesses already wow 
