David Cameron says protest violence was "unacceptable'
David Cameron has condemned the violence that broke out during protests over tuition fees after the Met Police announced an investigation into how it was handled.
The prime minister said the clashes in central London, which led to 35 arrests and 14 injuries, were "unacceptable".
He praised the "brave" officers who tried to control the crowds, but said "there weren't enough of them".
Met chief Sir Paul Stephenson called Wednesday's events "an embarrassment".
Seven police officers were among those hurt during the protests outside Conservative Party headquarters in Millbank on Wednesday.
Windows were smashed, fires lit and missiles thrown at police after a minority of protesters broke away from the main demonstration against a planned rise in university fees.
Some broke into the building itself, although hundreds of workers, including Tory Party staff, had already been evacuated.
Mr Cameron said he had watched events unfold from Seoul, where he was attending a G20 summit, and had been concerned: "I was worried for the safety of people in the building because I know people who work in there, not just the Conservative Party, but other offices as well, and so I was on the telephone."'Thin blue line'
Sir Paul apologised to those left inside the building for their "traumatic experience" and said the Met should have been better prepared for the possibility of violence.
End Quote Aaron Porter National Union of Students president
If we're now having to spend time talking about the rights and wrongs of violence and criminal damage, I think it undermines our argument”
"It's not acceptable. It's an embarrassment for London and for us," he said.
"I think we've also got to ask ourselves some questions. This level of violence was largely unexpected and what lessons can we learn for the future."
Mr Cameron said the situation had been "extremely serious" and welcomed the decision to hold an inquiry.
"I could see a line, a thin blue line of extremely brave police officers, trying to hold back a bunch of people who were intent on violence and destruction.
"They were very brave those police officers, but as the police themselves have said there weren't enough of them and the police response needs to reflect that, so I'm very glad that the Met Police commissioner has said what he said."
The PM said he would not abandon his plan to reform tuition fees - and allow some institutions to charge up to £9,000 a year - and insisted it was "a more progressive system than the one that it will replace".
Asked whether the protests reminded him of the sort of unrest seen under Margaret Thatcher's Conservative government in the 1980s, Mr Cameron said: "There have been protests, both peaceful protests and sometimes protests that have turned quite nasty, under all governments, so I don't see it like that."
National Union of Students (NUS) president Aaron Porter told BBC Breakfast his members had "lost a lot of public sympathy" because of what happened.
"What we had done was assemble 50,000 students which I'm sure would have got a hell of a lot of attention and would have sent a clear message to government," he said.
"But if we're now having to spend time talking about the rights and wrongs of violence and criminal damage, actually in many respects I think it undermines our argument rather than allowing us to concentrate on the devastation to our universities and colleges."
Former Flying Squad commander John O'Connor accused the Met of having "no tactics and nowhere near enough people" at the scene, and said it was "naive" of them not anticipate the threat from anarchist groups aiming to infiltrate the protest.
"It's an absolute disgrace," he told the BBC.
"I don't understand how anybody could have sat there planning that event and not taken the contingency plan into consideration that this is likely to erupt into violence."