St Martin-in-the-Fields is an Anglican church at the north-east corner of Trafalgar Square in the City of Westminster, London. Its patron is Saint Martin of Tours.
The earliest extant reference to the church is from 1222, with a dispute between the Abbot of Westminster and the Bishop of London as to who had control over it. It was decided in favour of Westminster, and used by the monks of Westminster Abbey.
The church was rebuilt by Henry VIII in 1542 to avoid plague victims from the area having to pass through his Palace of Whitehall. At this time, it was literally "in the fields" in an isolated position between the cities of Westminster and London.
By the reign of James I the church was becoming inadequate for the congregation, due to the great increase in population in the area. In 1606 the king granted an acre of ground on the west side of St. Martin's Lane for a new churchyard, and the church was enlarged.
Because of its prominent position, St Martin-in-the-Fields is one of the most famous non-cathedral churches in London. Its ethos as the "Church of the Ever Open Door" (a title coined by Dick Sheppard, Vicar in the early 20th century when the work with homeless people was started) continues today, even though it is not possible for it literally to be the case. It is famous for its work with homeless people through The Connection at St Martin's which shares with The Vicar's Relief Fund the money raised each year by the BBC Radio 4 Appeal's Christmas appeal. The church is also known for its regular lunchtime and evening concerts: many ensembles perform there, including the Academy of St Martin-in-the-Fields, which was co-founded by Sir Neville Marriner and John Churchill, a former Master of Music at St Martin's.