MercoPress. South Atlantic News Agency

Britain's Queen Elizabeth II turns 83

HM Queen Elizabeth II

The monarch will be spending the day privately at Windsor Castle with the Duke of Edinburgh.

Union flags will be flown above Government buildings until sunset in her honour, while the King's Troop Royal Horse Artillery will provide a 41-Gun Salute in central London using six 13 pounder First World War guns drawn by Irish draught horses.

The gun salute tribute takes place in Green Park this year because of refurbishments under way in the usual venue, Hyde Park.

Princess Elizabeth Alexandra Mary was born at 2.40am on April 21 1926 - the first child of the then Duke and Duchess of York - at 17 Bruton Street, the Mayfair home of her mother's parents, the Earl and Countess of Strathmore.

She is the great-great-grandchild of Queen Victoria, the last female sovereign.

The octogenarian Sovereign carried out 417 engagements in 2008.

Queen Elizabeth II, who is Head of State, the Armed Forces, the Commonwealth and the Church of England, has been married to Prince Philip for more than 61 years, has four children and is grandmother to eight grandchildren.

Her official birthday in June, is celebrated with the Trooping the Colour parade.

The Duke reached his own milestone last week. He became the longest serving consort in British history, overtaking the record of 57 years and 70 days set by Queen Charlotte, wife of King George III