The proposals, from the Sentencing Guidelines Council, which is headed by Britain’s most senior judge, were condemned last night as sanctioning a two-tier system for dealing with rape.

The council advises judges that “date rape” or “acquaintance rape” is as serious as “stranger rape”. An offender who ignores a victim’s wishes is guilty of rape, it says. But judges are then told that where consensual sexual activity takes place before the rape, it “must have some relevance for sentencing purposes” — although this is not defined.

Six years ago a Home Office review rejected the idea of a lesser offence of “date rape”. Ruth Hall, of Women Against Rape, said the concept was now being resurrected “by the back door”.

Ms Hall said that the council, headed by Lord Phillips of Worth Matravers, was “talking out of both sides of its mouth”. She said: “The council has had to bow to pressure that rape is rape — whatever the relationship between victim and offender, whenever it is done and whatever the circumstances. But on the other hand, the same prejudices are being brought in by the back door.”

She said that the idea that a rape after consensual sexual activity should command a lesser sentence was also “insulting” to men. “It implies that they reach a certain point and are simply unable to stop — like a washing machine cycle.

“Women have a right to change their minds; or to go so far and no further — perhaps because they don’t like what they are being asked to do or because the man turns violent.”

Last year the number of rapists successfully prosecuted fell to a record low despite a rising number of attacks. One in 18 reported rapes end in a conviction, while in the ten years to 2004-05 reported rapes rose from 5,136 to 14,002.

Rapes where victim and offender know each other are thought to make up 80 per cent of the 14,000 reported rapes a year. Of those “acquaintance” rapes, the ones that involve previous sexual activityare hardest to prosecute. Juries often believe that victims “asked” for it — because of behaviour, drinking or clothing.

Levels of sentence will be left to judges’ discretion. The re-commended starting point for adult rapes is five years. The guidelines say: “Any rape is a traumatic and humiliating experience” and “whether the offender is an acquaintance, an ex-partner or a current partner is not, of itself, relevant to consideration of the starting point for the sentence”.

It also says that anyone involved in “consensual non-penetrative activity” has the right to refuse penetrative sex. An offender who ignores victim’s wishes “is guilty of rape”. But if an offender and victim know each other and there is consensual sexual activity, that must have an impact on sentence, it says.

The paper — the first guidance on sexual offences — covers some 50 sex offences from rape to sex with a corpse or an animal. At present 98 per cent of rapists receive a custodial sentence and the average length of sentence is 7½ years.The Director of Public Prosecutions, Ken Macdonald, QC, said the guidelines should not lead to lower sentences.

“Indeed they recommend higher sentences if aggravating circumstances, such as the extreme youth or age of a victim, apply.”

Yesterday Professor Martin Wasik, chairman of the Sentencing Advisory Panel, said the guidelines were “simply stating accepted case law.” The breach of trust involved in a rape by someone known to the victim could make it as serious an offence as a “stranger” rape. But the more difficult area involved rapes where the couple had sexual familiarity.

The panel took the view that there was a difference between someone who set out to rape a person he knew; and “a situation where rape occurs after sexual familiarity, up to and perhaps very close to, actual intercourse — and then the victim said ‘no’.”

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Reported rapes (male and female):

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