Young rapists go on the register for only a year from the date on which they are cautioned after admitting the sex attack, The Times has learnt. Yet a rapist convicted in the courts and given a jail term of 2½ years is on the register for the rest of his life.

The huge disparity in the registration requirement between a rapist who is cautioned and one who is convicted will fuel demands for the Government to give more details about the circumstances behind the 40 rapists a year who are given cautions. It will also heighten suspicion among women’s groups that rape is still not being treated seriously by the police and justice system.

A Home Office official confirmed that rules governing how long offenders cautioned for sex offences, including rape, should spend on the sex offenders register had been relaxed under a law that came into force in 2004.

He said: “The requirements for cautions were reduced because cautions were not treated as seriously as offenders found guilty in the courts.” The change was a result of a consultation exercise undertaken before an overhaul of the sex laws in England and Wales.

Under the old rules an adult — over 18 — cautioned for rape would have been put on the sex offenders register for five years, but on May 1, 2004, this was reduced to two years.

Anyone under 18 cautioned for rape now goes on the register for only 12 months instead of 30 months under the old rules. But an offender jailed for rape for thirty months would be on the register for life, and someone given between six and thirty months would be on the register for ten years.

Last night women’s groups and anti-rape campaigners said that the discrepancy reinforced their view that the justice system was not treating rape seriously enough.

Meena Patel, of Southall Black Sisters, said: “The Government is saying that cautions for rape are being used in only the most exceptional circumstances. But then why are rapists only going on the register for such a short period? They should be on the register for longer than one to two years.”

Women’s groups continued to demand more details of cases where cautions had been given for rape, but there was little information supplied by the Home Office, Crown Prosecution Service or police.

The CPS said that two rapists cautioned in 2004 had been males under 18 involved in family rapes. Other examples are a pensioner cautioned last year for raping his sister when they were children 50 years ago. In another case a boy aged 13 was cautioned for raping a young child.

There were signs of exasperation at the Home Office over the failure of the police and the CPS to provide more examples of cautions for rape to reassure the public that they were being used properly. A statement from the department said: “We feel that a caution is not an appropriate sanction for rape. However, the police and CPS must have flexibility to act in the best interests of the victim in exceptional circumstances.”

The CPS defended the use of cautioning, insisting that it was used in only exceptional circumstances. Clare Ward, of the CPS, said that figures had been fairly stable at about forty cautions a year since 2000. Nick Clegg, the Liberal Democrat home affairs spokesman, said: “The police, Government and the courts must do more to reassure victims of rape that their attackers will be caught and properly sentenced.

“There are rare cases where a caution might be appropriate for someone who has committed rape. However, every effort should be made to bring rapists to trial.”

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