A Grenadier Guardsman who appeared to entertain tourists by pirouetting and performing silly walks while keeping guard outside Buckingham Palace is being investigated by the Army.

In a video, which can be viewed above, the unidentified soldier appears to mess around while on duty outside the Queen's official London home.

Guarding royal palaces is a prestigious ceremonial duty usually carried out by the five regiments of Foot Guards and occasionally by military units from countries where the Queen is head of state like Canada.

The soldier is seen in the clip, posted on YouTube last month, walking outside the Palace from his sentry box to a wall a short distance away.

As he marches up and down he stoops to pick something up, then on another patrol stops mid-stride with his foot in the air for a few seconds.

On another occasion the Guardsman performs a jaunty walk and later varies his speed and is also seen pirouetting three times before stopping outside his sentry box.

It is not known if the Queen or any other member of the Royal Family were at the royal palace.

Many of the comments below the video clip criticise the unknown soldier but one person defends him saying: "Have a day off you lot. This is one of the most boring jobs in the British army and he is injecting a little artistic licence into it for the crowds."

An Army spokeswoman said: "We are aware of the video. Anyone who is found to fall short of the Army's high standards can expect to face appropriate action."