It became a principal parish church west of the old City in the early modern period as Westminster's population grew.

When its medieval and Jacobean structure was found to be near failure, the present building was constructed in an influential neoclassical design by James Gibbs in 1722–1726.

It is possible that the Saxon town of Lundenwic essentially grew eastwards from the early burial group (Museum of London Archaeology).

[citation needed] The earliest extant reference to the church is from 1222, when there was a dispute between the Abbot of Westminster and the Bishop of London as to who had control over it.

[4] Henry VIII rebuilt the church in 1542 to keep plague victims in the area from having to pass through his Palace of Whitehall.

The ceiling was slightly arched,[6] supported with what Edward Hatton described as "Pillars of the Tuscan and Modern Gothick orders".

[6] The interior was wainscotted in oak to a height of 6 ft (1.8 m), while the galleries, on the north, south and west sides, were of painted deal.

His first suggestion was for a church with a circular nave and domed ceiling,[7] but the commissioners considered this scheme too expensive.

[5] The west front of St Martin's has a portico with a pediment supported by a giant order of Corinthian columns, six wide.

The panels are decorated in stucco with cherubs, clouds, shells and scroll work, executed by Giuseppe Artari and Giovanni Bagutti.

J. P. Malcolm, writing in 1807, said that its west front "would have a grand effect if the execrable watch-house and sheds before it were removed" and described the sides of the church as "lost in courts, where houses approach them almost to contact".

[9] Although Gibbs was discreetly Catholic, his four-wall, long rectangular floor plan, with a triangular gable roof and a tall prominent centre-front steeple (and often, columned front-portico), became closely associated with Protestant church architecture world-wide.

This churchyard, which lay to the south of the church, was removed to make way for Duncannon Street, constructed in the 19th century to provide access to the newly created Trafalgar Square.

Dick Sheppard, Vicar from 1914 to 1927 who began programmes for the area's homeless, coined its ethos as the "Church of the Ever Open Door".

The church is famous for its work with young and homeless people through The Connection at St Martin-in-the-Fields,[15] created in 2003 through the merger of two programmes dating at least to 1948.

[16] The crypt houses a café which hosts jazz concerts whose profits support the programmes of the church.

The crypt is also home to the London Brass Rubbing Centre, established in 1975 as an art gallery, book, and gift shop.

A life-sized marble statue of Henry Croft, London's first pearly king, was moved to the crypt in 2002 from its original site at St Pancras Cemetery.

The almshouses were built in 1818, in Bayham Street (to a design by Henry Hake Seward),[23] on part of the parish burial ground in Camden Town and St Pancras and replaced those constructed in 1683.

It supports 4000 homeless people in London each year, by providing accommodation, medical and dental care, skills training, and creative activities.