State and official visits to the United Kingdom

Donald and Melania Trump with Queen Elizabeth II, the Prince of Wales and the Duchess of Cornwall prior to attending a state banquet at Buckingham Palace in London.
Nicolae and Elena Ceaușescu with Queen Elizabeth II and Prince Philip, Duke of Edinburgh at Buckingham Palace during a visit in the UK, June 1978.

State and official visits to the United Kingdom are formal visits by the head of state of one country to the United Kingdom, during which the British Sovereign acts as official host of the visitor. It is a royal event that involves all the assets in the Civil Service, the Royal Household and the Household Division. It also involves other members of the Royal family and is centred in London, the national capital. Invitations for state visits are sent by the Royal Household with supervision by the Foreign and Commonwealth Office.

State visits do not formally occur between the United Kingdom and the 14 other Commonwealth realms, as the realms all share a common monarch and head of state. Visits conducted by the monarch to another Commonwealth realm are also not considered a state visits but rather royal visits. In addition, official visits to the United Kingdom by another Commonwealth realm are typically performed by their respective governor general, who in that capacity are usually in the country for an audience with the King.