More than half a million serial criminals have escaped with repeated cautions in 'soft justice' Britain.

In tens of thousands of cases, offenders are committing four or more crimes such as shoplifting or burglary, and still not being hauled before the courts.

Critics said it made a mockery of the idea that cautions should be used to warn the first-time offender that if they step out of line again they will be punished by magistrates or judges.

The Tories blamed the Government's target culture for making prosecutors prefer to take the easy option of settling a case outside court. Half of crimes are now dealt with by 'soft penalties', such as cautions or on-the-spot fines.

Figures obtained by the party's police spokesman David Ruffley show that, between 2000 and 2008, an astonishing 2.2million have received police cautions.

Of these, 550,000 have received repeat cautions, including 51,874 people who have received four or more slaps on the wrist.

The number of criminals receiving two cautions in a single year has increased by 60 per cent, from 21,842 in 2000 to 34,785 in 2008, while the number getting three cautions in a single year has increased by 45 per cent, from 3,934 to 5,714.

Most worryingly, the number receiving four or more cautions in a single year has increased by 21 per cent, from 2,480 to 3,013.

Over the eight years, 23,588 people have received four or more cautions in a single year. Some 104,915 have received three cautions and 397,458 have received two cautions.

Crimes commonly punished by cautions include theft, burglary and violence. But in some cases they are even handed out for sex attacks and rape.

Critics have blamed the Government's obsession with targets for the rise in cautioning. Under the 'Offenders Brought to Justice' target, a fine or caution carries the same weight as a prosecution through the courts.

Police have warned that prosecutors are opting for cautions rather than taking criminals to court, which costs more money and does not guarantee a conviction.

Officers also warn that the Crown Prosecution Service is downgrading the seriousness of crimes. They give the examples of actual bodily harm (ABH) being downgraded to assault and drug-dealing to possession of drugs.

Last night Mr Ruffley said: 'Soaring numbers of police cautions for repeat offenders means they are not going to court as most people would expect.

'Many police say that this is because the Crown Prosecution Service can be risk-averse when deciding to take a case to court - hence the rise in police cautions.

'That is why the Conservatives propose to give the power back to the police to charge rather than caution in more cases. Repeat offenders should expect to face court, not a "slap on the wrist" caution.'

Cautions were supposed to be given only once, as a final warning. But a controversial instruction given to police and prosecutors by the Home Office last year said they could give serial criminals a string of cautions rather than drag them to court.

The Home Office guidance said anyone caught committing the same 'trivial' offence again could be let off with a caution. providing two years had passed.

It means a thief could receive up to five cautions in ten years without ever facing a court.

The note, called Simple Cautioning of Adult Offenders, also advises that any offender caught committing multiple crimes in a single incident can still escape with a caution. Instead of adding all the offences together to create a picture of a serious criminal, each may be treated separately.

For example, if a person arrested for being drunk and disorderly also admits he was planning to use keys to steal from cars, he could be given a penalty notice for the drunk and disorderly offence and a caution for going equipped to steal.

Mr Ruffley said: 'This is a scandal. It sends out the wrong message to career criminals. A repeated slap on the wrist will not deter people from going on to commit more crimes.

'The first caution should be the last one. People should expect to go to prison if they continue to break the law.'