What is Trooping the Colour?
Trooping the Colour is the official annual celebration of the Queen's birthday. This year it falls on Saturday, June 17.
Otherwise known as The Queen's Birthday Parade, it is a chance for the Queen, 91, to inspect soldiers from her personal troops, the Household Division.
The colourful display of pageantry features 1400 officers and men on parade, 200 horses and 400 musicians from 10 bands. The Queen always attends and takes the salute.
According to the Household Division, 113 words of command are given by the Officer in Command of the parade.
How can I watch it?
The parade takes place on Horse Guards Parade behind Whitehall, London from 10am and is televised live by the BBC from 10am.
It's too late to get tickets now. Tickets for the seated stands around Horse Guards were allocated by ballot earlier this year and cost £30 following applications made in writing before the end of February.
However, the Queen and other members of the Royal family travel to and from Buckingham Palace in carriages, so there is ample opportunity to see her for anyone standing on The Mall.
The public can also admire the spectacle during the two rehearsals. The first, known as The Major General's Review, takes place on June 3 while the The Colonel’s Review takes place on June 10. Both can be seen from The Mall or the edge of St James's Park.
What happens during the parade?
The Queen leaves Buckingham Palace in a carriage (she used to travel by horse) accompanied by a Sovereign's escort from the Household Cavalry Mounted Regiment at 10am.
She arrives to take the Royal salute from the officers and men on parade at 11am and then carries out an inspection of the troops wearing the ceremonial uniform of red tunics and bearskin hats.
The Regimental Colour (flag) being trooped is then carried down the ranks following music by the bands. This year it's the 1st. Battalion Irish Guards.
The Foot Guards and the Household Cavalry then march past Her Majesty, and The King's Troop, Royal Horse Artillery, rank past with their guns.
The Queen rides back to Buckingham Palace and appears on the balcony with members of the Royal Family at 1pm to watch a fly-past by the Royal Air Force.
When did Trooping the Colour begin?
The ceremony is believed to have been first performed during the reign of Charles II and in 1748 it was decided that the parade would be used to mark the official birthday of the sovereign.
An annual event since 1760, it has been the practise for the regiments of the sovereign’s own Household Troops to troop their Colours in turn.
The Queen has taken the salute at every parade since her accession to the throne 62 years ago, except in 1955 when there was a national rail strike.
Where did the tradition originate?
Colours were the regimental flags of the British Army which displayed the uniform Colours and insignia of different units. They were designed to help troops quickly identify their unit on the battlefield and avoid confusion.
In order for troops to be familiar with their regiment's Colours, it was necessary to display them regularly. So, young officers would march in between the ranks of troops stood in lines holding the Colours high. This is where the word 'trooping' comes from.
Wasn't the Queen's birthday in April?
Yes - she has two birthdays. Here's why.