Taser gun used on man with knives outside Buckingham Palace Published duration 3 February 2013

media caption Mobile footage, courtesy of Josh Greenberg and Grant Shepherd, shows the man being Tasered before police disarm him

Police have used a Taser stun gun on a man who was brandishing two knives outside Buckingham Palace in London.

An officer discharged the weapon when the man, thought to be in his 50s, acted aggressively when challenged outside the centre gates at 11:50 GMT.

The Metropolitan Police said he had been arrested on suspicion of affray.

Two knives and a pair of trainers were left inside a police cordon set up around the area. The Queen and Prince Philip were at Sandringham at the time.

Changing the Guard

A spokesman for the Met said: "A man was seen outside the centre gate in possession of two knives.

"He was not making threats to members of the public but he was challenged by police.

"He acted aggressively and a Taser was discharged."

The man was spotted with the weapons during the Changing the Guard ceremony, which hundreds of tourists and Londoners had gathered outside the palace to see.

Eyewitness Kevin Burrows, 33, from Surrey, said: "There must have been about 15 police officers on foot who surrounded him once he'd been Tasered. The police saw him really quickly and were obviously cautious."

He added: "Everybody was standing back when it happened and people were actually quite calm, I think everyone was surprised."