Lancaster House was built in 1825-29, the grandest and only free-standing of the mansions in St James's, set in a large garden. It was designed as York House by Benjamin Wyatt for the Duke of York, who died in 1827 before it was finished. It was taken over and completed by the 2nd Marquess of Stafford, later 1st Duke of Sutherland, and became the focus of the family's social and political life. In 1913 the lease was purchased for the nation by Sir William Lever, who renamed it Lancaster House. From 1924 it was used by the London Museum, but in 1952-3 it was restored by the Ministry of Works for conferences and government hospitability, a use that continues today. The gardens are surrounded by wall and railings of 1833, behind which is a thick yew hedge and shrubbery, the garden front giving onto a broad terrace from which steps descend to the lawn. Flanking the carriage entrance against the east garden wall are 2 huge stone statues of Sculpture and Architecture by E H Baily of 1828, which came from the east front of Buckingham Palace.
In the ownership of the Dukes of Sutherland, Stafford House was sumptuously decorated and contained the family's fine art collection. The attic storey was added in 1833-38, designed by Sir Robert Smirke, who had in fact presented a first design for York House in c.1820, rejected in favour of Wyatt's design of 1825. The grand staircase was the work of Sir Charles Barry. This palatial building became the fashionable venue for the Duke and Duchess of Sutherland's many visitors from the world of liberal politics and the arts, who included reformer Lord Shaftesbury, anti-slavery author Harriet Beecher Stowe and Italian nationalist leader Garibaldi as well as Queen Victoria. After Sir William Lever, Lord Leverhume, presented the house to the nation, Lancaster House was used for some years as the London Museum, but this ceased after WWII. As a government building under the remit of the Foreign and Commonwealth Office, Lancaster House has been the venue for many important occasions including the European Advisory Committee in 1944, the signing of Malaya's agreement of independence in 1956, the Lancaster House Agreement in 1979 when Zimbabwe gained independence from the UK, the 10th G7 summit in 1984 and the 17th G7 summit in 1991. It has also been used as a filming location on many occasions.