Britain today celebrated the 90th birthday of Queen Elizabeth II with gun salutes and fireworks and Prime Minister David Cameron paying tributes to the UK's oldest and longest-serving monarch calling her a "Rock of strength" for the country and the Commonwealth.
The monarch is spending her big day at one of her palaces outside London in Windsor Castle and began the day with a walkabout in the town.
Prime Minister David Cameron led the tributes by referring to the Queen as a "Rock of strength" while Prince Charles, the Queen's heir, recorded a special birthday message for his mother in which he reads an edited passage from William Shakespeare's Henry VIII for radio broadcast during the day.
In his birthday message, Cameron said: "Her Majesty The Queen has lived through some extraordinary times in our world.
"From the Second World War to the rations with which she bought the material for her wedding dress. From presenting the World Cup to England at Wembley in 1966 to man landing on the moon three years later. From the end of the Cold War to peace in Northern Ireland.
"Throughout it all, as the sands of culture shift and the tides of politics ebb and flow, Her Majesty has been steadfast - a rock of strength for our nation, for our Commonwealth and on many occasions for the whole world."
Cameron will lead tributes later in Parliament, which will be lit up overnight in the red, white and blue of the Union Jack.
A photograph of the monarch with young Royal Family members has been released.
The image, one of three taken by celebrity photographer Annie Leibovitz, shows the Queen surrounded by her five great-grandchildren and her two youngest grandchildren.
Royal Mail yesterday issued a set of 10 special stamps to mark the occasion, featuring four generations of UK monarchy with the Queen, Prince Charles, Prince William and Prince George.
The group family photograph taken last year appears as a stamp sheet, with perforations positioned to create a first class stamp for each of the four royals.
Gun salutes will take place around the UK starting from noon and Cameron will lead tributes to Britain's longest serving monarch in the House of Commons.
Some celebrations will be held across the country today but the Queen's official birthday celebrations for the nation will be held on the first weekend of June, which will include a grand charity street party near Buckingham Palace.
The queen was born Princess Elizabeth on April 21, 1926 and became queen on the death of her father, King George VI, in 1952. A majority of Britons have lived under no other monarch.
