A 'comedy terrorist' who gatecrashed Prince William's 21st birthday party was last seen in public throwing paint over a famous artist in Oxford.

Aaron Barschak

Aaron Barschak was dressed as Osama Bin Laden when he jumped on stage at Windsor Castle on June 21, as the Prince was making a speech of thanks, and shouted "I am Bin Laden!".

Security forces bundled Prince William out of the room and arrested 36-year-old Barschak before taking him to an undisclosed police station.

He was released on bail on June 22 and Home Secretary David Blunkett has demanded a report into how the comic managed to completely evade security at a party attended by most of the Royal Family at a time when the UK is on a high anti-terrorist alert.

On June 18, Barschak appeared at Oxford Magistrates' Court charged with criminal damage over an incident at Modern Art Oxford in which he is alleged to have thrown paint over Turner Prize nominee Jake Chapman on May 30. He was released on bail until July 15.

Modern Art Oxford in Pembroke Street had been showing The Rape of Creativity exhibition by Mr Chapman and his brother Dinos at the time. Oxford Mail reporter Samantha Simpson spoke to Barschak after his brief court appearance.

She said: "With his thick long hair, bushy beard and hippy-like clothes, he looked eccentric. I was surprised to hear him greet me with 'All right, darlin'.

"He was a little zany, but friendly and approachable -- a typical joker and maybe even a bit of a charmer.

"He told me I was pretty as a picture and that Modern Art Oxford should've put me on display rather than Jake and Dinos's work."

Barschak, of Dulwich, London, regularly dresses as the Al Qaida leader and goes by the name 'Comedy Terrorist'.

His previous targets include Ken Livingstone and Graham Norton.

His father, Fred Barschak, 72, a property developer from London, said his son would not have meant to harm anyone.

He said: "He is a professional stand-up comedian who is desperate to be a serious actor."