Under fire: Sir John Stevens

But the legal profession has hit back strongly, saying the scales of justice have already been tipped heavily in favour of the police.

Michel Massey QC said Sir John's comments contradicted the assumption of innocence until proven guilty and were "hilarious" because of their inaccuracy.

"The suggestion I find completely repulsive is the concept where a policeman decides to arrest and charge, therefore, ipso facto, this man is guilty," he told BBC Radio 4's Today programme.

'Miscarriages of justice'

On Wednesday, Sir John told students at Leicester University that the legal system favoured defendants and put victims and witnesses on trial.

Strict rules govern way lawyers operate

He said there was a real danger of civil unrest unless the criminal justice system was radically overhauled to stop the guilty walking free.

His comments were supported on Thursday by Chief Constable Peter Neyroud of Thames Valley Police, who said trials have become a game instead of a search for the truth.

The chief constable said the guilty will continue to walk free until trials are made more robust.

But Mr Massey said: "That's completely untrue. We've had in this country a series of miscarriages of justice which has forced major areas of change in areas of disclosure."

The Bar Council and the Law Society earlier attacked Sir John's comments, saying lawyers acted within strict rules to ensure they acted in the interests of justice.

'Anarchy'

Lord Mackenzie, former president of the Police Superintendents Association, said Sir John was not denying the assumption of innocence.

"We're talking about looking after the interests of the people who are not volunteers in this system, that's the victims and witnesses.

"It's a �60bn or �70bn (crime) industry and there are vested interests that have obviously a very great interest in prolonging the perpetuation of the faults in the system because they make a lot of money from it. It's a fat living."

Liberal Democrat home affairs spokesman Simon Hughes defended the police chief's right to air his views on how the criminal justice system should be improved.

Are victims' being marginalised?

He said: "Victims must have greater rights in the criminal justice system and witness protection must be hugely improved."

But he added: "We will not counter the frightening growth of violent crime by removing the rights of defendants to be tried by lay magistrates or lay juries.

In his speech, Sir John blamed defence lawyers for attacking witnesses' characters and police procedures.

He said that judges, defence lawyers and court administrators were protecting criminals at the expense of victims and witnesses.

Reform report

The commissioner called for "sweeping reform" or else victims and witnesses would "not even bother to turn up".

Sir John backed Lord Justice Auld's report on reform of the criminal justice system.

He was supported by Victims of Crime Trust chief executive Norman Brennan, who said anarchy was not far away.

But Harry Fletcher, of the probation union Napo, said the courts were already jailing more criminals than before.