An immediate inquiry into a security breach at Prince William's 21st birthday party has been ordered by Home Secretary David Blunkett.
A man was handcuffed and driven away by police
An intruder managed to get inside Windsor Castle as 300 guests celebrated with the prince and other senior royals.
Police arrested the unarmed 36-year-old man at 2320 BST on Saturday, and he is currently being held at a Thames Valley police station.
No one was injured during the incident at the African-themed party, but Scotland Yard said the matter was being treated seriously.
The intruder is believed to be Aaron Barschak, who lives in London.
Mr Barschak's father Fred told BBC News his son was a "comedy terrorist" who was trying to get publicity ahead of performing at the Edinburgh festival.
He said: "I think it's a high price to pay for publicity."
Police and royal security advisors are reviewing the incident, with an independent senior officer placed in charge.
A Home Office spokeswoman said on Sunday: "Depending on the outcome, [David Blunkett] may ask for a further inquiry."
A Scotland Yard spokesman said: "We consider any breach of security to be a serious matter and a thorough review into all the circumstances surrounding the incident is under way."
The intruder reportedly stumbled onto the stage as Prince William made a speech thanking Prince Charles and the Queen for organising the party.
BBC correspondent Clarence Mitchell said departing guests described how the man grabbed the microphone before security guards and police pulled him away.
The intruder shouted out that he was Osama bin Laden, and as he was driven away in handcuffs he was seen clutching a book about the al-Qaeda leader.
Our correspondent said that in these times of suicide bombings, the possible horror of such a security breach could not be contemplated.
A St James's Palace spokeswoman refused to comment on how the incident had affected the Royal Family and other party guests.
"Security is a matter for the Metropolitan Police and the ball is now in their court," she said.
All of the guests, including the Queen, wore fancy dress to the party.
The Windsor streets had a jungle flavour as guests arrived
There are several entrances to Windsor Castle, but most of the party-goers came in through the Henry VIII Gate.
As they arrived, police scrutinised guests' large red party invitations, and observed their vehicles.
Outfits spotted on guests arriving at the castle included a furry lion, Tarzan and a banana.
The castle's ancient rooms were transformed into scenes from the African bush, which include a life-sized elephant made out of papier mache.
African band Shakarimba had been flown in specially from Botswana where William heard them perform while on holiday four years ago.
The party theme - Out of Africa - was inspired by the prince's time in Africa during his gap year before university.
Among the guests were Camilla Parker Bowles, Earl Spencer and his sisters, and William's friends from St Andrews University in Scotland.
The earl arrived dressed in a light-coloured safari type suit, followed by the comedian Rowan Atkinson and his wife in linen and colonial-style attire.
Prince William said being King was his duty
Other outfits seen on arriving guests included a lion suit topped with a gold crown, a full foreign legion uniform, a Biggles-esque pilot, a banana and a top-hatted witch-doctor.
In an interview given to mark his birthday, Prince William rounded on his father's critics.
He also denied rumours he did not want to be king, saying it was his duty.
The prince is midway through a four-year degree course at St Andrews, studying history of art.