This is the dramatic moment a Queen's Guardsman shouts at an over-eager tourist who gets a little too close while moving in for a photo outside Windsor Castle.
As the oblivious visitor goes to pose for a picture, the guardsman booms: "Stay away!"
Stunned onlookers mutter as the startled man spins on the spot and offers an immediate salute after the order is barked in his ear.
The footage begins as four guards parade through the grounds of the castle in front a gaggle of camera-clutching tourists, who are soaking up the sights at the British landmark.
However, as the last of the group enters the castle grounds, he turns to shut a gate leading to the lawn, situated beside the State Apartments of the Upper Ward, the Daily Mail reported.
One of the public duties battalions or incremental companies are responsible for is providing the guard at Windsor Castle.
The location of the ceremony at Windsor varies; in the summer, when the Queen is in residence it usually takes place on the lawn in the Castle's quadrangle.
This is not the first time this year a Queen's Guard has had to rebuke tourists for careless actions or getting too close.
A dancing tourist outside St James's Palace was told off by a soldier, thought to be part of the Scots Guard regiment in a thick Scottish accent.
At the beginning of the video, which has racked up thousands of views, a man can be seen dancing on the spot outside the royal palace in London.
Suddenly one of the guards in the background wearing a distinctive bearskin hat and grey winter tunic shouts at the tourist ordering him to stop.
He says: "Haw, get yersel' away, ye came and ye done this yesterday anaw, do him wan, turn the camera aff."
That roughly translates as: "Listen, get yourself away. You came and did this yesterday too. Do him one, turn the camera off."
The embarrassed tourist can be seen quickly halting his dance and shuffling away.
Clad in their distinctive tunics and bearskins hats, the soldiers of the Queen's Guard are charged with protecting official royal residences.
The units, manned by fully-trained, serving soldiers, have more than 350 years of history and have defended monarchs since Charles II took the throne after the English Restoration in 1660.
There are thought to be guidelines in place for guardsmen to deal with nuisances, which begins with stamping their feet and shouting.
Raising a rifle is considered a "final warning", after which the guardsmen is allowed to detain the person in question.