The British Army's Household Division enjoy the honour of guarding the Sovereign and the Royal Palaces.
Household troops, better known as 'the Guards', have guarded the Sovereign since 1660.
It is worth remembering that even though the regiments of the Household Division may often be seen on ceremonial duty, they all remain operational soldiers with their primary role as part of a combat force.
The dual role of the Household Division
The Queen is Colonel in Chief of all the regiments in the Household Division, which consists of two regiments of the Household Cavalry and five regiments of Foot Guards.
The regiments that form the Household Division have a long and proud history, mostly dating back to the time of the English Civil Wars and the Restoration in the middle of the 17th Century.
Since that time they have proudly carried out a dual role as the sovereign's personal troops and as operational soldiers for the nation.
Headquarters Household Division sits within the larger Headquarters London District with the unique responsibility for delivering state ceremonial and public duties, primarily in London and Windsor.
The headquarters is based at Horse Guards on Whitehall in central London.
Watch: Irish Guards practise Trooping the Colour ahead of Platinum Jubilee celebrations.
The breakdown of the Household Division
The five Foot Guards regiments that are a part of the Household Division are:
The Grenadier Guards: One of the most senior infantry regiments in the British Army. Fast and mobile, they specialise in Light Role Infantry operations.
Renowned for their dual role, they serve on overseas exercises and on the battlefield as well as carrying out ceremonial duties in London and at Windsor Castle.
The Coldstream Guards: They are infantry soldiers who specialise in light role operations. Their versatility makes the regiment one of the most important fighting units in the British Army.
Coldstream Guards also have the ceremonial role as protectors of the Royal palaces. The Regimental Band of the Coldstream Guards is one of the oldest and best-known military marching bands in the world.
The Scots Guards: They are a Mechanised Infantry that trains to use speed to cross the battlefield quickly and launch onto difficult objectives, one of the first units with a new fleet of vehicles at the forefront of British Army capability.
In addition to their combat role, the regiment's ceremonial company has the special honour of acting as guards at Royal residences.
The Irish Guards: The Irish regiment is known affectionately throughout the Army as 'the Micks'.
Its soldiers also have the privilege of guarding Royal palaces.
The Welsh Guards: As a Light Role Infantry they are able to lead from the front as a mobile and flexible attack force and deploy on operations around the world.
They also have the role of ceremonial soldiers, guarding the Royal Family and Royal palaces and conducting state ceremonial duties.
These regiments, along with the two cavalry regiments, the Life Guards and the Blues and Royals, form the Household Division.
The Life Guards: This cavalry unit is the senior regiment in the British Army, having been formed in the 1650s.
It is now part of the Household Cavalry and operates as both an armoured reconnaissance unit and a ceremonial guard to the monarch.
The Blues and Royals: Formed in 1969, the unit is part of the Household Cavalry.
It is the second-most senior regiment in the British Army and operates as both an armoured reconnaissance unit and a ceremonial guard of the monarch.
Watch: What's the military's role in the Queen's Platinum Jubilee?
The Queen is Colonel-in-Chief of all the regiments of the division and each regiment has a colonel who is either a member of the Royal family or a senior officer.
Each June, one of the five Foot Guards regiments is selected to troop their Colour at the Trooping the Colour parade, held to commemorate the sovereign's official birthday.
Their role is largely ceremonial, with the police providing the bulk of actual security protection for the Queen and other members of the Royal Family, but the guards do still carry rifles fitted with a bayonet.
When carrying out ceremonial duties in London and at Royal residences such as Windsor Castle, the foot guard regiments will be in their recognisable scarlet tunics and bearskins.