The Carlton House Fête is held in London to celebrate the establishment of the Regency era.

The Carlton House Fête was hosted on 19 June 1811 by the Prince Regent, the future George IV, at his London residence Carlton House. Ostensibly held to honour the exiled Louis XVIII and French royal family, it functioned as a celebration of the establishment of George as Regent on behalf of his father George III. The lavish event set the tone amongst High Society during the Regency era.

London is the capital and largest city of both England and the United Kingdom, with a population of 8,945,309 in 2023. Its wider metropolitan area is the largest in Western Europe, with a population of 15.1 million. London stands on the River Thames in southeast England, at the head of a 50-mile (80 km) tidal estuary down to the North Sea, and has been a major settlement for nearly 2,000 years. Its ancient core and financial centre, the City of London, was founded by the Romans as Londinium and has retained its medieval boundaries. The City of Westminster, to the west of the City of London, has been the centuries-long host of the national government and parliament. London grew rapidly in the 19th century, becoming the world's largest city at the time. Since the 19th century the name "London" has referred to the metropolis around the City of London, historically split between the counties of Middlesex, Essex, Surrey, Kent and Hertfordshire, which since 1965 has largely comprised the administrative area of Greater London, governed by 33 local authorities and the Greater London Authority.

The Regency era of British history is commonly understood as the years between c. 1795 and 1837, although the official regency for which it is named only spanned the years 1811 to 1820. King George III first suffered debilitating illness in the late 1780s, and relapsed into his final mental illness in 1810. By the Regency Act 1811, his eldest son George, Prince of Wales, was appointed Prince Regent to discharge royal functions. The Prince had been a major force in Society for decades. When George III died in 1820, the Prince Regent succeeded him as George IV. In terms of periodisation, the longer timespan is roughly the final third of the Georgian era (1714–1837), encompassing the last 25 years or so of George III's reign, including the official Regency, and the complete reigns of both George IV and his brother and successor William IV. It ends with the accession of Queen Victoria in June 1837 and is followed by the Victorian era (1837–1901).