Trooping the Colour was traditionally part of the military's preparations for battle, but in 1748 it was announced it would also be held to mark the sovereign's birthday. The Queen actually turned 83 on 21 April.
The Duke of Edinburgh sat beside the Queen during the parade. She has attended Trooping the Colour every year throughout her reign, except in 1955 when it was cancelled due to a national rail strike.
Princes William and Harry travelled in another horse-drawn carriage with the Duchess of Cornwall. Prince William, who is training to be a military helicopter pilot, wore his Royal Air Force uniform.
Prince Harry wore the uniform of his regiment, the Blues and Royals.
Crowds lined The Mall to get a glimpse of the popular young Royals as they were taken from Buckingham Palace to Horse Guards Parade.
The Earl and Countess of Wessex were joined by the Duke and Duchess of Gloucester in the second carriage. The procession was accompanied by a Sovereign's Escort of the Household Cavalry.
The precision marching was enjoyed by spectators from around the UK and abroad, as well as the Royal Family.
After surviving one of the toughest weeks of his political career, Prime Minister Gordon Brown was joined by his wife, Sarah, at Horse Guards.
The Queen took the royal salute under a cloudy blue sky during the televised ceremony as senior Royals looked on.
Another of her duties in the ceremony is to inspect the troops, wearing red tunics and bearskin hats.
Her Majesty travelled in Queen Victoria's 1842 ivory mounted phaeton carriage. Behind her on horseback in ceremonial military uniform were Prince Charles, Princess Anne and the Duke of Kent.
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