Elizabeth Alexandra Mary Windsor was born in London to King George VI and Queen Elizabeth on 21st April, 1926. This birthday she usually celebrates privately with family at Windsor Castle, but she has another which is a rather more public event.

The Queen's "official birthday" is held on the third Saturday in June each year for the very pragmatic reason that the British weather is usually better in June than in April. It is attended by many state dignitaries, members of the Armed Forces as well as members of the public.

The celebration centres on Trooping The Colour or if you prefer, The Queen's Birthday Parade, a colourful military parade which takes place on Horse Guards Parade, Whitehall in London.

The troops who participate are always from the Household Division and it is one Foot Division of the Grenadier, Coldstream, Scots, Irish and Welsh Guards which takes it in turns to have their colour trooped or carried along the ranks each year.

The Household Division is part of the British Army therefore both the Horse and Foot Troops are fully trained and capable of operational duties, but it is by tradition, their honour to guard the Monarch.

The ceremony originates from a mixture of two historical military ceremonies - Trooping The Colour and Mounting The Queen's Guard - both of which involved parading the battalion colour or flag in front of the troops in order that they could recognise it should it be used as a rallying point in battle.

It was in 1748 that it was deemed that Trooping The Colour would mark the official birthday of the Sovereign and since the reign of King Edward VII, the Monarch has taken the salute in person. Queen Elizabeth II has taken the salute every year of her reign except when a rail strike caused the parade to be cancelled in 1955.

During the ceremony at Horse Guards Parade, The Queen takes the Royal salute and inspects the troops, which from 1969 to 1986 she did in uniform from the back of the charger, Burmese. Now, however, she is driven in a phaeton and takes the salute from a platform wearing mufti. The massed bands perform a musical troop and the regimental colour for the year is paraded along the ranks. The troops then march or ride past The Queen. The Queen then returns to Buckingham Palace at the head of the Guards, before taking the salute once again, following which the troops return to barracks.