The Government is poised to introduce legislation to control strictly drugs that can be used in date rape cases.
At the end of this month, the Home Office will receive a specially commissioned Metropolitan Police report into drug-assisted sexual assaults.
The report, which comes after a detailed inquiry into drug rape, will urge the Government to consider banning drugs used to dope and rape women. Aides to the Home Secretary, Jack Straw, last night confirmed that "ministers would act on advice received".
Demands for action are certain to be heightened by findings in the report revealing a marked increase in the crime.
MPs are already campaigning for some drugs to be banned or more tightly controlled after a string of sex cases, thought to have involved drugs such as Gamma Hydroxy Butyrate (GHB), available over the counter, and the prescription drugs Rohypnol and Ketamine. Deaths have also been caused by mixing GHB with alcohol.
Detective Inspector Peter Sturman, the officer in charge of the review, told the Independent on Sunday that there was evidence to link up to four drugs to sex attacks. "There are certainly indications that they are being used for drug-assisted assault. Indications are that it may be on the increase," he said.
But Mr Sturman warned that trying to count the numbers of cases was "difficult if not impossible". "To be honest, once you have established it is happening, every one is one too many. That is why we need to do something about it."
An outright ban on the drugs is just one option that he will ask Mr Straw to consider. "We obviously need to consider the banning of drugs but we need to look at the other implications to ensure a ban has a positive outcome rather than a negative outcome," he said.
Mr Sturman said that in the shorter term tougher controls could be introduced to stem supply and misuse.
GHB, banned in the United States, is unlicensed in Britain but is available over the counter to ease sleeping disorders. Odourless and colourless, it can be easily slipped into drinks. The police will suggest that Mr Straw changes the law controlling the availability of the drug and brings in stiffer penalties for people who commit drug-assisted sexual assaults.
"There is obviously a need for tighter controls and harsher penalties," Mr Sturman said.
South Wirral MP Ben Chapman has been campaigning for GHB to be banned since the death of his constituent Iain Hignett, who died after mixing the drug with alcohol. He said last night that he believes the Government will, ultimately, opt for an outright ban. "I am confident that ministers are sympathetic to my point of view and I am confident that they are moving towards it."
A senior aide to Mr Straw said: "On all these issues we are led by science and the evidence and there is a proper procedure for this. If the advice is that there should be a change it would be of great weight."