A campaigner dressed as Batman, from the fathers' rights group that pelted British Prime Minister Tony Blair with flour-filled condoms, caused a major security breach today by scaling the front wall of Buckingham Palace.
Police talked the man down after five hours on a small ledge some 10 metres (30 feet) off the ground at Queen Elizabeth's London residence, lifting him to safety on the arm of a cherry-picker.
The royal family is currently away on holiday in Scotland.
The campaign group Fathers 4 Justice said police had threatened to shoot a would-be accomplice who was dressed as comic hero Batman's sidekick Robin.
Mr Darly Westell, a spokesman for the protesters, said "We created a diversion at the front gates of the palace to allow Batman and Robin to walk up to the side with long ladders and climb over the fence."
"Police threatened to shoot Robin unless he got down from the fence -- which we think is unacceptable because this is a peaceful, non-violent protest. But Batman was able to continue."
The Batman protester unveiled a banner on the front of the palace saying: "Super Dads of Fathers 4 Justice fighting for your right to see your kids."
The group believes British courts are biased against fathers in child access arrangements in divorce cases.
Metropolitan Police Commissioner Sir John Stevens told BBC radio the security breach was embarrassing and he had called for a full report to be on his desk by Tuesday morning.
"If it had been someone carrying a bomb and it had been assessed he had been carrying a bomb, he would have been shot," he said.
British Home Secretary David Blunkett is due to make an emergency statement on the matter to the House of Commons later today.