'Batman' protest at queen's palace
Man dressed as Batman protests on Buckingham Palace ledge.
LONDON, England (CNN) -- London's police chief has demanded an urgent inquiry after a fathers rights campaigner dressed as Batman evaded supposedly tight security to stage a protest on a Buckingham Palace balcony.
Officers, facing their second security breach in four months after the group pelted Prime Minister Tony Blair with flour-filled condoms, took five hours to finally bring the protester down from Queen Elizabeth's London residence.
A police spokeswoman told CNN that a man was arrested on Monday night in connection with the incident on suspicion of causing criminal damage.
Police said no members of the royal family were in the palace but admitted the protester should not have been able to scale the perimeter fence with a ladder and climb onto the high-profile balcony.
Scotland Yard issued a statement saying London police chief Sir John Stevens had demanded a report on the incident by Tuesday morning.
Stevens said "the intruder was readily identified as performing a publicity stunt but if he had been carrying a gun or a bomb he would probably have been shot," the statement added.
"He said that the CCTV (close-circuit television monitoring) and the alarms worked and the police response was speedy but nevertheless it was unacceptable that the wall had been scaled and he would ensure that whatever was necessary would be done in relation to improved security."
Former Buckingham Palace spokesman Dickie Arbiter said officials would be seriously embarrassed by Monday's incident.
He told Sky News: "They will be very seriously embarrassed by what has happened, and they will be looking at ways now to really tighten up on possibly even public access, and make it even harder to get in.
"But they've made it hard already, so how much harder they can make it in the light of this I don't really know."
The campaign group Fathers 4 Justice said the man scaled the palace's outer fence helped by a would-be accomplice dressed as comic hero Batman's sidekick Robin.
Meanwhile, other protesters distracted the attention of armed police by climbing on the front gate.
The group said police had threatened to shoot Robin unless he got down from the fence, "which we think is unacceptable because this is a peaceful, non-violent protest." Police declined to comment on the incident.
The protester dressed as Batman, wearing grey tights, black pants and cape, the superhero's bat symbol and a mask with pointed ears, then climbed up on the palace balcony -- which is used by the royals for ceremonial occasions.
Standing on a ledge to the right hand side of the balcony, about 8 meters (25 feet) above the ground, he unfurled a banner that read: "Super dads of fathers 4 justice."
Also on the banner were the words: "Fighting for your right to your kids."
After spending five hours trying to persuade the protester to come down, police on a cherry picker finally removed him at 7.20 p.m.
Royal security was reviewed after a Daily Mirror reporter got a job at Buckingham Palace as a servant before U.S. President George W. Bush stayed there during a state visit in November last year.
Stand-up comedian Aaron Barschak also highlighted lax security by gate-crashing Prince William's 21st birthday party at Windsor in June last year.
Fathers 4 Justice, which says Britain's courts are biased against fathers in divorce cases involving child access, are notorious for their publicity stunts.
Its attack on Blair in the House of Commons four months ago caused a massive security alert amid fears of a terrorist attack and prompted changes to access rules for parliament.