How did Bin Laden in drag make it to William's bash?

An embarrassing breach of royal security, in which a self-styled "comedy terrorist'' dressed in a bizarre Osama bin Laden outfit, gatecrashed Prince William's 21st Birthday party at Windsor Castle and joined him on stage, was the subject of a Home Office inquiry yesterday.

Aaron Barschak, a stand-up comedian who calls himself the Comedy Terrorist, briefly grabbed the microphone from the Prince - in the middle of a speech thanking his father and the Queen for organising the party - and began shouting. As he was hauled away by security guards he declared: "You can see me next Monday."

Many guests initially believed he was part of the entertainment at the party, which had an Out of Africa fancy-dress theme. Prince William said jokingly afterwards: "I didn't know my brother could do an accent like that."

Before the party, Mr Barschak, who has a history of disrupting events, flaunted himself for photographers outside the castle, pulling up his pink dress to reveal a pubic wig. It is not known whether he somehow obtained or forged an entry ticket, or whether he simply evaded the security screen.

Mr Barschak was arrested on suspicion of burglary, which covers unauthorised entry. Later yesterday, he was seen back at the castle, literally helping Scotland Yard with their inquiries, by showing them exactly how he gained access. As he was being driven away he gave a four-finger wave to the waiting tourists, in a style which mocked the Queen's wave.

He was bailed to return to a London police station next month.

Despite the comic aspects of the incident, the Home Office and Scotland Yard want to know how the man managed to get so close to Prince William and the other Royals. It was the most serious breach of royal security since 1982 when an intruder, Michael Fagan, found his way into the Queen's bedroom at Buckingham Palace.

A Home Office spokesman said that David Blunkett, the Home Secretary, had ordered an immediate report on the incident from the Metropolitan Police, who are responsible for royal security.

Mr Barschak's previous on-stage targets have included Ken Livingstone, the Mayor of London, and the comedians Terry Jones and Graham Norton. He is said to have thrown a tin of red paint over the artist Jake Chapman, who was giving a lecture in Oxford Museum, entitled "The Lack of Spontaneity in Art". The paint also damaged his Turner prize nomination, The Rape of Creativity.

His father, Fred Barschak, 72, a property developer from north London, said: "I can believe it was him. He would not have been trying to harm anyone. He is a professional stand-up comedian who is desperate to be a serious actor."

About 300 people attended the party. Guests included the comedian Rowan Atkinson, society celebrity Tara Palmer-Tomkinson and his uncle, Earl Spencer. A band from Botswana entertained the crowd. Prince William, who is said to be teaching himself Swahili, was inspired for the party theme by his trips abroad, including his gap year spent partly in Tanzania, Kenya and Botswana.

Royal intruder, page 5