The Household Cavalry handed over their duties to the Royal Canadian Mounted Police to guard Her Majesty The Queen at Horse Guards Parade in 2010.
Re-enacting a gesture made by her father, King George VI, in 1936, HM The Queen has seen fit to celebrate the Commonwealth
by inviting the Royal Canadian Mounted Police to take part in British ceremonial this summer.
A strong relationship between the Royal Family and the Mounties was forged in 1904
when The Queen's grandfather, King Edward VII
Granted the Canadian Mounted Police the prefix 'Royal' in recognition of the Force's many services to Canada and the Empire.
On Tuesday 23 May 2010 - 15 men and horses from the Royal Canadian Mounted Police proudly rode down the Mall
For the 11 o'clock Changing of The Queen's Life Guard ceremony with the Household Cavalry.
After special training by members of the Household Cavalry riding staff
the Mounties performed the centuries' old tradition, for real, for one day only.
The Sovereign's personal body guard, known today as The Queen's Life Guard
have been guarding the ceremonial entrance to the Royal residence since the 17th Century.
Today, The Queen's Life Guard are best known for the iconic London image of a mounted Trooper
rigidly sitting on his horse in a sentry box on Whitehall, surrounded by crowds of tourists.
Ahead of the event, Regimental Corporal Major Warren Brown, the Household Cavalry's senior soldier, said: -
"I flew out to Canada to teach the Mounties how to do the Changing of the Guard
and I was pleasantly surprised by how quickly they all picked it up.
It's not easy learning someone else's drills, commands and ceremonies when you haven't had hundreds of years of that tradition passed down to you.
"They will be using our Cavalry Black horses, and they can be quite a handful if you are not used to riding horses as huge as ours.
Thankfully, they are all excellent horsemen and women, and used to riding in busy urban environments."
The Guard is normally made up of 15 soldiers, including a captain, when Her Majesty is in residence, and lasts for 24 hours.
At 1100hrs every day, the off-coming Guard are replaced by the new Guard during a half-hour ceremonial ritual on Horse Guards Parade ground.
The Household Cavalry's red-coated Life Guards and blue-coated Blues and Royals are the guardians of this historic role.
However, a strong Canadian link was forged prior to the coronation of The Queen's father, King George VI.
In 1937, the Royal Canadian Mounted Police were given the honour of meeting Her Majesty after riding out of Hyde Park Barracks
using the same route as The Queens Life Guard. In 2000, Lord Strathcona's Horse - The Household Cavalry's Canadian cousins - mounted The Queen's Life Guard.
To date, the Canadians are the only foreign unit to have been awarded this honour
The only other British unit to mount The Queen's Life Guard is The King's Troop Royal Horse Artillery.