CAMPAIGNERS last night condemned a "failing system" after figures showed nearly 700 sex offenders in the region had escaped with police cautions in the past five years.

A total of 691 cautions were issued by four police forces for sex offences, including nine for rape.

Northumbria Police was second to London's Metropolitan Police for the number of cautions for sex offences recorded in the past five years.

The Association of Chief Police Officers said offenders were not being "let off", since the caution was noted on a criminal record and were entered on the sex offenders' register.

But the scale of the number of cautions - an alternative to being charged and taken to court - was criticised and there were claims it masked a wider problem. In the Cleveland force area, 129 cautions were recorded, including two for rape.

There were 66 in Durham, including one for rape, 50 in North Yorkshire (none for rape) and 446 in Northumbria (six for rape).

Dr Nicole Westmarland, a criminology lecturer at Durham University, has acted as an advisor to the Government, chairing an expert group on rape and sexual abuse.

She said: "Cautions are not the way forward, but they are one way of dealing with a system that is failing."

Dr Westmarland, who is chairwoman of Rape Crisis England and Wales, added: "If we had proper punishments for men who rape and sexually offend you would not have to look for backdoor options of getting convictions in this way."

Redcar MP Vera Baird, a barrister and rape victim campaigner, said she believed the cautions attributed to her own force, Cleveland, were "not excessive", but she added that she intended to seek a full explanation from Cleveland Chief Constable Sean Price.

She said: "It must be an extraordinary occurrence when the police should be permitted to caution. It must never cover an unwillingness to investigate the crime properly."

Nationally, almost 8,000 people were cautioned for sex offences across England in the past five years, according to figures obtained by the BBC from 38 police forces in England.

Sex crimes include offences such as rape, downloading child pornography, indecent exposure, incest, bigamy and prostitution.

Inspector Jason Dickson, head of the Child Abuse Investigation Team at Cleveland Police, said: "Crimes like rape are taken extremely seriously. A caution is only considered where a prosecution is not possible."

Northumbria Police said a change in Home Office counting procedures had contributed to the number of cautions for rape.

It said that before April 2004, a caution was recorded as a rape when initially reported, even if on investigation it was discovered that an offence of a lesser nature had been committed.

Five of the six rape cautions recorded in the past five years fell into this category with only one being recorded since the change.

Superintendent Mick Hassen, of Northumbria Police, said: "All reports of sexual offences are fully and properly investigated and decisions to proceed by way of a caution are taken following full consultation with appropriate individuals and careful consideration of all of the issues involved."