The Metropolitan Police struck the "wrong" balance between cracking down on violence and allowing the right to protest during yesterday's student fees demonstration, Police Minister Nick Herbert has said.
Policing of the protest "clearly did not go to plan", Mr Herbert said, telling MPs that the force would "learn the lessons" from the scenes which saw demonstrators storm the building housing Conservative Party HQ and led to 50 arrests.
In a Commons statement on 11 November 2010, Mr Herbert said the blame for the "appalling" violence, in which 41 police officers were injured, lay solely with the perpetrators.
Shadow home secretary Ed Balls agreed, describing yesterday's vandalism as "completely unacceptable" and carried out by "thugs".
Mr Herbert said: "The police have to strike a balance between dealing promptly and robustly with violence and unlawful activity on the one hand, and allowing the right to protest on the other.
"Clearly, in this case, the balance was wrong. But these are difficult decisions and they are not taken lightly."
A probe had been launched by the Met to examine why the number of demonstrators and the scale of violence had not been anticipated, Mr Herbert said.
Mr Balls said that "a small minority of thugs" had "hijacked what was planned to be a legitimate and peaceful demonstration, and in so doing denied tens of thousands of students and lecturers the right to have their voices properly heard".