Media playback is unsupported on your device Media caption The BBC's Andy Tighe says questions will be asked over the royal 'ambush'

Questions have been raised about police handling of tuition fee protests after a car carrying the Prince of Wales and the Duchess of Cornwall was attacked.

A window was smashed and paint thrown at the vehicle as the royal couple made their way to a central London theatre.

Violent demonstrations spread after MPs voted to increase university tuition fees in England.

Met Police chief Sir Paul Stephenson said the royal attack was shocking and there would be a full inquiry.

'Thugs'

Mark Pritchard, Conservative MP for The Wrekin, questioned police tactics.

Media playback is unsupported on your device Media caption Sir Paul Stephenson: "Any right minded individual, including peaceful protesters, will condemn what has happened today"

He told the BBC: "We've got 'kettling' that is supposed to confine people in an area to stop violence spilling out to other areas, and clearly it has not worked.

"Therefore, the planning and control and the senior management decisions by the Metropolitan Police over this whole incident need to be looked at."

Metropolitan Police Commissioner Sir Paul Stephenson said the attack on the royals was "very shocking" and they should be commended for their fortitude.

He also said the route was "thoroughly recced" in advance, including several minutes beforehand, and that his officers had shown "commendable restraint".

He said: "The unpredictability of the - I was going to say demonstrators but I'd rather describe them as thugs - and how they moved about the capital meant that the protection officers were placed in a very difficult position.

"Yesterday was a thoroughly disgraceful incident and there will be a very full and detailed criminal inquiry into how that attack happened."

London Mayor Boris Johnson said it was regrettable the heir to the throne could be surrounded by agitators and that people's first instinct was to blame the police.

And Universities Minister David Willetts said the attacks on the police were "shocking" and the officers caught up in the violence should be supported.

"The police were in very difficult circumstances and they were being tested over hours, often of abuse and attack. I don't think it's for us who were not on the front line like they were to criticise them," he told the BBC.

The National Union of Students (NUS), meanwhile, said the violence had overshadowed the story it wanted to see in the newspapers.

Shane Chowen, vice-president of further education, said: "Not the headlines I wanted. I wanted to see the fact that the coalition government have just trebled tuition fees, sentencing a generation of students to record student debt."

The prince and duchess, who were travelling to the London Palladium for the annual Royal Variety Performance, were unharmed.

Prime Minister David Cameron said it was "shocking and regrettable" that protesters had attacked the prince's car.

Clarence House said the royal couple were safe and had attended the performance as scheduled.

Media playback is unsupported on your device Media caption Theresa May condemns the "appalling levels of violence"

The former head of royal protection, Dai Davies, told BBC Radio 4's Today programme he was "appalled" by the attack on the royals and surprised by the apparent lack of strategy.

He said: "One of the principles of protection is to have alternative routes and I would have expected there to be at least three different routes.

"I'm surprised, and clearly the commissioner is embarrassed and surprised also, why there isn't better co-ordination - or appears to be - between those in charge of protection and those marshalling and dealing with the riots."

The Commons vote mean fees will almost treble to £9,000 a year. The government's majority was cut by three-quarters to 21 in a backbench rebellion. Three ministerial aides resigned.

Only 28 Lib Dem MPs - fewer than half - voted for the government's plans for tuition fees. Six Conservative MPs voted against.

Students from around the UK gathered in London for a day of protests and a rally - with police expecting about 20,000 demonstrators.

In angry scenes, protesters battled with police in Parliament Square. Hundreds were contained on Westminster Bridge for a time by officers.

There were angry clashes as protesters - some throwing missiles - fought to break through police lines.

Riot police had to force back protesters who were smashing windows of the Treasury and the Supreme Court.

Earlier, protesters had largely taken over Parliament Square and pressed against lines of police in front of the Houses of Parliament.

How the vote went 28 Lib Dem MPs voted yes

21 Lib Dem MPs voted no

8 Lib Dem MPs either abstained or were absent

6 Conservative MPs voted no

2 Conservative MPs abstained Full list: How Lib Dems voted

Mounted police were used to control crowds, at one point charging a group of protesters.

Scotland Yard said 12 officers and 43 protesters were injured, and 34 people were arrested.

Supt Julia Pendry said officers had come under sustained attack and condemned "acts of wanton vandalism, wanton violence" by protesters.

Police said there were attacks using "flares, sticks, snooker balls and paint balls".

The Metropolitan Police Authority chairman, London Deputy Mayor Kit Malthouse, defended the tactic of holding of demonstrators in a small area, known as "kettling".

He said: "You either go for dispersal of the crowd, and we've seen that in London in the past, what you then get is groups of protesters ranging through London.

"The other alternative is to contain, and that often calms the crowd down.

"Now, obviously these crowds can be very volatile and people can break away, and that seems to be what's happened."

Home Secretary Theresa May said she "utterly condemned" the violence.

Media playback is unsupported on your device Media caption Ben Brown: "It's been quite a battleground"

"What we are seeing, the wanton vandalism, smashing of windows, has nothing to do with peaceful protest," she said.

"I have spoken to Paul Stephenson and he has updated me on the appalling levels of violence.

"Attacks on police officers and property show that some of the protesters have no respect for London or its citizens."

She said the "next steps" in relation to the attack on the royal car were down to the police.

The coalition government faced its first major backbench rebellion in the vote.

The package of measures will see fees rising to an upper limit of £9,000 per year - with requirements for universities to protect access for poorer students if they charge more than £6,000 per year.