Their costumes may have been comical but the issues raised when Batman and Robin effortlessly defied security at Buckingham Palace were far from a laughing matter.
Security arrangements at royal residences were placed under the spotlight last night following the apparent ease with which the infiltration took place.
Surveillance was stepped up only recently in the wake of a series of problems and exposés of security failings. Last year, Ryan Parry, a Daily Mirror reporter, gained employment at the palace as a footman just before a state visit by President George Bush. In the aftermath of the breach, an immediate review was launched while officials also appointed Brigadier Jeffrey Cook as director of security liaison.
A sophisticated alarm system had already been installed at Buckingham Palace after the 11 September terror attacks when a major review was made of security by MI5 at the main royal palaces.
It was hoped, however, that appointing Brigadier Cook would enable the palace to bring its arrangements in line with the 21st century in a radical reform of security surveillance. The latest incident is likely to place him under pressure as officials had given assurances that security were to be tightened and improved. Buckingham Palace is not the only royal residence to have been exposed as having security failings. In June last year, Aaron Barschak, a self-styled "comedy terrorist", highlighted lax procedures at Windsor Castle by infiltrating Prince William's 21st birthday party dressed as Osama bin Laden.
Only a week after Brigadier Cook was appointed in May, a man was arrested after gaining entry into Windsor Palace by posing as an undercover police officer. Last night, it was clear that the latest lapse would cause considerable embarrassment among officials. The two Fathers4Justice campaigners managed to bypass armed police guards and sophisticated security mechanisms in broad daylight using the most basic of strategies.
Fellow protesters used the age-old technique of distracting the armed police guards by climbing the front gate. Meanwhile, Jason Hatch and his accomplice managed to scale the outer fence using a ladder, before climbing to a first-floor ledge 25 feet above the ground.
While the alarm system was believed to have been activated, questions were raised as to why officers at the scene failed to mobilise sooner to prevent their progress.
Last night, David Blunkett, the Home Secretary, said that the Metropolitan Police, Home Office officials and the Royal Household were "urgently reviewing any further measures required".
But he defended the actions of the police and highlighted the activation of the alarm system. "While today's protest showed the alarm and camera system worked, the protester could have been killed and the Metropolitan Police once again diverted away from protecting the public from terrorism and into dealing with a public stunt."
Sir John Stevens, the Metropolitan Police Commissioner, was more outspoken in his critique. "The alarms and CCTV operated," he said. "The police response was speedy but he got inside the perimeter. It's not good enough and we want to know how this happened."
The fact that there were no members of the Royal Family in residence at the time is likely to provide scant relief. Dickie Arbiter, a former spokesman for Buckingham Palace said: "This is the first time any incident of this nature has happened through the 11 years the palace has been open... They will very seriously be embarrassed by what has happened."
Steve Park, a security specialist, told Sky News: "The police have been caught out and they should have been more alert to deal with a simple security breach. I don't understand how somebody could have made their way across 30 metres of the grounds and scaled the wall to the first floor."
1982: Perhaps the most famous royal security incident was when Michael Fagan broke into the Queen's bedroom. The monarch woke to find Fagan, 30, sat on her bed. They reportedly chatted before he was apprehended.
1994: A naked American paraglider landed on the Buckingham Palace roof. American James "Fanman" Miller was deported and fined £200 for the stunt.
June 2003: At Prince William's 21st birthday party, Aaron Barschak gained access to the fancy dress do at Windsor Castle attired as Osama bin Laden in a beard and cocktail dress. Once inside, he persuaded police officers that he was a guest.
November 2003: Security was reviewed after Ryan Parry, a 'Daily Mirror' reporter, managed to secure an £11,000-a-year job at the palace as a footman before a state visit by US President Bush.