It is the Queen’s duty as Head of State to formally open each new session of Parliament.
The State Opening of Parliament forms the most colourful event of the Parliamentary year and is steeped in tradition and customs dating back centuries.
It used to take place in the autumn each year, but since 2010 it is usually scheduled for May thanks to the introduction of five-year fixed-term parliaments.
Before the Queen travels to Parliament from Buckingham Palace, certain historical ‘’precautions’’ are observed.
The Yeomen of the Guard, the oldest of the royal bodyguards, arm themselves with lanterns to search the cellars of the Palace of Westminster, a practice which dates back to the Gunpowder Plot of November 5 1605.
This is followed by a more scientific police search.
Another tradition sees a Government whip held ‘’hostage’’ at the Palace to ensure theQueen’s safe return.
The custom dates back to centuries when the monarch and Parliament were on less cordial terms.
Once the safety measures have been observed, the Queen travels from her London home in a horse-drawn state coach to Westminster, accompanied by the Duke of Edinburgh.
The royal couple will be escorted by the Household Cavalry Mounted Regiment and street liners will guard the whole route and present arms as the royal party passes.
Lining the route of the procession will be servicemen from 1st Battalion Grenadier Guards, Nijmegen Company Grenadier Guards, Number 7 Company Coldstream Guards, F Company Scots Guards, 1st Battalion Welsh Guards, detachments of the Royal Navy and the Royal Air Force.
The Regalia - the Imperial State Crown, the Cap of Maintenance and Sword of State - travel in their own carriage, ahead of the monarch, escorted by senior members of the royal household.
The Prince of Wales and Duchess of Cornwall will join the Queen and Philip at Westminster, travelling in another horse-drawn state coach - the third successive year Charles and Camilla have taken part in the event.
As the Queen reaches the House of Lords, a 41-gun salute will be fired by The King’s Troop Royal Horse Artillery, supported by the Band of the Royal Artillery, in Green Park.
On arrival, the Queen puts on the Imperial State Crown and her parliamentary robe ready for the ceremony itself in the House of Lords.
No monarch has set foot in the House of Commons since Charles I entered the Commons and tried to arrest five Members of Parliament in 1642.
The Queen is met at the Palace of Westminster’s Sovereign’s Entrance by the Earl Marshal and the Lord Great Chamberlain, who, as Keeper of the Royal Palace, wears scarlet court dress and has hanging at his hip the golden key to the Palace.
As the Queen moves up the Sovereign’s Staircase to the Robing Chamber, she passes between two lines of dismounted Household Cavalry soldiers in full dress with drawn swords.
They are the only troops allowed to bear arms within the Royal Palaces. After putting on the Imperial State Crown and parliamentary robe, the Queen leads a procession through the Royal Gallery, packed with more than 600 guests, to the Chamber of the House of Lords, where she takes the throne.
The Sovereign’s Procession is led by senior parliamentary and government officers, including the Lord Chancellor, the Lord Speaker of the House of Lords and the Lord Privy Seal.
The Great Sword of State and the Cap of Maintenance, symbols of the Sovereign’s power and authority, are carried in front of the Monarch.
When the Queen sits down, the Lord Great Chamberlain signals to an official, known as the Gentleman Usher of the Black Rod, in his capacity as the Sovereign’s Messenger to summon the House of Commons and demand their presence.
As he approaches the Commons, the door of the Chamber is slammed in Black Rod’s face to demonstrate the supremacy of the Lower House over the Lords.
He knocks three times with his Black Rod, from which he derives his name, and is finally admitted.
Black Rod says: ‘’Mr Speaker. The Queen commands this Honourable House’’ - bowing to the left and to the right as he does so - ‘’to attend Her Majesty immediately in the House of Peers.’’
This tradition is a reminder of the right of the Commons to exclude everyone but the Sovereign’s messengers.
The Serjeant-at-Arms, carrying the mace, leads the procession to the Lords followed by the Commons Speaker and Black Rod.
The Prime Minister, the leader of the opposition and MPs follow them, and when they reach the Lords chamber they stand at the opposite end to the throne, known as the bar.
The Queen’s Speech is delivered to the throne by the Lord Chancellor in a special silk bag.
Although the Queen reads the speech, the content is entirely drawn up by the Government and approved by the Cabinet.
The final words, ‘’other measures will be laid before you’’, give the Government flexibility to introduce other legislation as necessary.
When the Queen leaves, the Royal Standard is taken down and the Union Flag hoisted. In the afternoon Parliament goes back to work, with each house meeting separately to begin debating the content of the speech.
The Queen has opened Parliament on all but two occasions throughout her reign. These were 1959 and 1963, when she was pregnant with Prince Andrew and Prince Edward.