Footage captures Queen's guardsman roughly shoving a female tourist.

The Queen‘s Guard are famously steely and unflappable. But one tourist has learned the hard way what happens when you get in their way.

Footage has emerged online of a guardsman roughly shoving a woman outside Windsor Castle.

The clip, which was reportedly recorded on Sunday, shows the woman posing for a photograph on the wrong side of the crowd-containment rope, right in the path of the marching officer. When she fails to move, he pushes her firmly in the back.

The shocked woman screams as she stumbles forward, and ducks quickly out of the way.

And the guardsman goes right on marchin’ past her.

The Queen’s Guard consists of five infantries of fully-trained, full-service soldiers who protect the Royal residences. Though famously disciplined, interference from the public has resulted in the majority of the guardsman being posted out of reach.

The rope seen in Sunday’s incident at Windsor Castle, for example, was placed there following a 2015 incident in which a guardsman was forced to turn his rifle on a tourist.

Footage of that encounter shows the man mockingly walking alongside the marching officer before placing a hand on his shoulder.

The guardsman spins around, raises his weapon and yells, “Get back from the Queen’s Guard!”

In a statement about the latest incident quoted by The Sun, Britain's Ministry of Defence issued a plea to the public.

“The Household Division is proud to guard Her Majesty and honoured that people come from around the world to watch our ceremonial spectacle," the statement read.

"The ropes are there to protect both the public and our soldiers; please stay behind them.”