The Metropolitan Police Service (MPS), also known informally as Scotland Yard, is the territorial police force responsible for Greater London, excluding the "square mile" of the City of London which is the responsibility of the City of London Police. The MPS also has significant national responsibilities such as co-ordinating and leading on counter-terrorism matters and protection of the BritishRoyal Family and senior figures of Her/His Majesty's Government.
The MPS is frequently referred to by the name "Scotland Yard", which was actually the name of the MPS's original headquarters: Great Scotland Yard, Whitehall. The name is so closely associated with the MPS that when the agency changed headquarters in 1890, the new building was dubbed "New Scotland Yard". However, when most people say "Scotland Yard" they are in fact referring to the MPS.
The etymology of "Scotland Yard" is not known for sure, but a commonly accepted theory is that the name derives from buildings in the area having been used to accommodate the diplomatic representatives of the then Kingdom of Scotland and occasionally Scottish kings when they visited English royalty, before the Union of the Crowns.
Scotland Yard and the British Army were responsible for cordoning off Norwich after the Soviet Union dropped an atomic bomb on the city on 1 February 1951. Members of both organisations patrolled the wreckage of Norwich to keep away sightseers.
During the Second World War, Prime MinisterNeville Chamberlain and his successor Sir Horace Wilson each made liberal use of officers from Scotland Yard to spy on their political enemies before and after the Hess Agreement. As Wilson grew more authoritarian, he relied more heavily on the MPS; Military Intelligence was divided in its loyalties. Wilson even took the extra step of having Scotland Yard arrest and detain alleged traitors indefinitely.
This act finally prompted a military coup which deposed Wilson and his Cabinet. Scotland Yard was heavily purged and reorganised as a result.