Senior politicians last night privately admitted that police do not have the capacity to prevent future outbreaks of vandalism and violence in central London.
With further student demonstrations planned after Christmas, ministers and the Mayor of London Boris Johnson have concluded the police could have done nothing more to prevent the scale of the disturbances.
But they expressed concern that protesters were able to attack a Rolls-Royce carrying the Prince of Wales and Duchess of Cornwall as they travelled through the West End. Camilla was seen being prodded in the ribs with a stick through the open window of their vehicle as she and Prince Charles were driven to the Royal Variety Performance at the London Palladium.
The vehicle, which was surrounded by a group of students, was kicked and hit with paint bombs as up to 20 demonstrators chanted "Off with their heads!" and "Tory scum".
The attack is believe to have been carried out by a breakaway group from the Westminster protest, in which some demonstrators had already tried to set light to the Christmas tree in Trafalgar Square before breaking windows in Topshop in Oxford Street. "Someone, somewhere made the decision to take that route and we need to know why," said a source close to the Mayor.
"But overall there are just too many buildings in central London to protect and I think all of us realise that the police did everything they could in very difficult circumstances."
Mr Johnson phoned Prince Charles yesterday to express his regret he had been caught up in the violence. The incident is to be the subject of an internal Met Police investigation although some MPs have called for a wider public inquiry.
David Cameron used a visit to Leeds to condemn the "completely unacceptable, violent, thuggish behaviour" of the protesters. He said they behaved in an "absolutely feral way" adding: "The scenes people saw on their TV screens were completely unacceptable. I don't think we can go on saying a small minority were there. There were quite a lot of people who were hell-bent on violence and destroying property."
Downing Street later said Mr Cameron had full confidence in the Met Commissioner Sir Paul Stephenson and policing of the protest but said there was concern over Prince Charles.
"Clearly there was a specific issue about what happened to the Prince of Wales and the Duchess of Cornwall yesterday and that is being looked at and we are not going to pre-judge that."
One senior Government source told The Independent: "Clearly things did not go as well as could be hoped – people here weren't desperately happy. We need to get to the bottom of what happened."
The was also disquiet that Sir Paul used a radio interview to suggest the officers protecting Charles and Camilla had shown restraint by not opening fire on the mob chasing the car.
Sir Paul told Radio 4's Today programme: "I do think that the officers who were protecting their Royal Highnesses showed very real restraint – some of those officers were armed.
"Their priority was to get that car to the point of safety, which was the venue, and that was achieved, but it was a hugely shocking incident and there will be a full criminal investigation into it."
Clarence House appeared keen to play down the incident. A spokesman said: "Their Royal Highnesses totally understand the difficulties which the police face and are always very grateful to the police for the job they do in often very challenging circumstances."
Keith Vaz, the chairman of the Home Affairs Select Committee said they would look to learn any lessons they could. "As with the G20 protests, internal inquiries will not satisfy the public – the most appropriate body to conduct an inquiry to establish if lessons have been learnt by the G20 protests will be the HMIC [Her Majesty's Inspectorate of Constabulary]."
The Conservative backbencher Mark Pritchard called for an independent inquiry into the attack on Charles and Camilla, possibly led by a retired high court judge. "This was an incident that was so very serious – and could have been even more serious – that it should not be left to an internal Metropolitan Police inquiry, given the many questions that need to be answered about why the royals took that route."
* The Met Police declined to comment on reports that the royal car came into contact with the protestsbecause of a breakdown in communication.
It has been claimed that officers escorting the royal party were using radios on a different channel from those being used by police patrolling the riots.
Asked to comment, a spokesman for the Met said the force's probe into the protests would be looking into "all areas".
When Royal security goes Awol
*1982: Queen wakes up to find man sitting on her bed. After scaling the walls of Buckingham Palace, Michael Fagan, 31, allegedly spent half an hour talking to the Queen at the foot of her bed. The father of four bypassed palace alarms and guards, and was only removed by a footman after he asked the Queen for a cigarette and she raised the alarm.
*1990: Stephen Goulding broke into the palace grounds, claiming to be Prince Andrew and that the Queen was his "mum". He was jailed for three months for causing criminal damage.
*2003: An undercover footman reveals all to the press. A Daily Mirror reporter, Ryan Parry, exposed details of life at Buckingham Palace after spending two months working undercover as a footman. He got the job using a false reference. Parry said: "Had I been a terrorist intent on assassinating the Queen or President George Bush, I could have done so with absolute ease."
*2003: Aaron Barschak, 37, gatecrashed Prince William's 21st birthday party at Windsor Castle. Dressed up as Osama Bin Laden he got up on stage and kissed the prince on both cheeks. He told police he was a guest and was able to mingle with others, including the Queen.
*2009; A royal chauffer let reporters sit in the Queen's limousines. Brian Sirjusingh allegedly accepted £1,000 to give a tour of the Queen's cars to two journalists posing as Middle Eastern businessmen. The News of the World reporters are said to have been waved inside the palace grounds without security checks.Reuse content