The National Physical Laboratory where Alan Turing worked is located in Teddington.
Teddington is a suburban town in the London Borough of Richmond upon Thames, on the southwest side of Greater London. The laboratory’s historic base is Bushy House, in the grounds of Bushy Park, where the NPL was established in 1900.
Turing worked at the NPL from 1945 to 1947 after the Second World War. His principal project was the Automatic Computing Engine, or ACE, an ambitious design for a stored-program electronic computer. The ACE proposal anticipated many features of later general-purpose computers, although Turing left before the complete machine was built.
A frequent error is to answer “London.” That is geographically understandable because Teddington lies within Greater London, but the question asks for the town, so Teddington is the more precise answer. Manchester is associated with Turing’s later work on the Manchester computers, while Oxford was not the location of the NPL.