A chief constable has told of his despair at the justice system for letting suspects, including robbers and gunmen, back on to the streets on bail to repeatedly reoffend.

Bernard Hogan-Howe said police have been left 'frustrated' and 'struggle to understand' what is happening in the country's courts.

The Merseyside police chief gave the shocking example of a man caught for three separate robberies who was freed on bail each time.

He cited the case of another thug caught in a car containing two loaded guns who was given bail - instead of being sent to jail on remand - on the condition he wore a tag.

He tore off the tag and was hauled back to court, only to be freed again on the same conditions.

Mr Hogan-Howe told a fringe meeting at the Labour Party conference it seemed bail was now being granted except 'only in the most serious circumstances of violence'. And

he added in an interview with the Daily Mail last night: 'The police and the public are worried about violent crime at the moment.

'When we have successes, we need the support of the courts and the criminal justice system to detain suspects before their guilt or otherwise is established.

'If suspects are allowed out on bail, there is a danger they will harm or interfere with witnesses, or commit further offences.'

Mr Hogan-Howe added that in more serious cases there should be an 'assumption' that suspects remained in custody.

His criticism, backed by crime victims and rank-and-file officers, came as a blow to John Reid on the day he laid the foundations for a leadership challenge by promising to be tough in crime.

It amounted to a criticism of the Home Secretary's policies. Only last month, Mr Reid sent a memo to magistrates urging them to consider freeing suspects with electronic tags, rather than lock them up. This was viewed as a desperate

step to ease overcrowding in Britain's jails, which have fewer than 700 spaces left.

Mr Hogan-Howe described how a man was arrested after ?44,000 was snatched from a security guard, who was threatened with a knife.

He said: 'We discovered the person had been arrested three times since March for different types of robberies and had got bail every time. We struggled to understand why he was still on the street.'

In a separate incident on September 9, police pulled two men over in a routine stop and found two handguns, both loaded, in the boot of their car.

One man was kept in custody because he was an illegal immigrant. But the other was released on a tag, which he later removed. This resulted in him being rearrested. Despite taking off his tag, he was given bail again with the same conditions by a court.

Mr Hogan-Howe said 90 per cent of those charged with robbery offences were eventually convicted.

Shadow Home Secretary David Davis blamed the problem on a lack of capacity in Britain's prisons.

He added: 'This means no one wins - the victim gets no justice, the offender gets no rehabilitation and the public get no protection.'

Norman Brennan, director of the Victims of Crime Trust, said magistrates were giving criminals a 'licence to rob and rob again', adding: 'As far as I am concerned, unless there are exceptional reasons, offenders should be refused bail before being given the toughest of penalties.'

Jan Berry, chairman of the Police Federation, said: 'It is enormously frustrating and demoralising and leaves you questioning why you are doing it.'

The Home Office insists the final decision on who should be tagged or bailed remains with the courts.

John Thornby, deputy chairman of the National Association of Magistrates, said: 'Offenders have a right to bail and the only reason they can be refused is if there are particular concerns about reoffending or failure to turn up to later appearances.

'Having a long record is not a reason to refuse bail.'