London, November 19 : Sex with prostitutes trafficked into the country, or who work for pimps or drug traffickers, may soon be a criminal offence in Britain.
According to plans set out to clamp down on prostitution, accused persons would not be able to take the defence of ignorance of the new law, or of a woman's circumstances.
Home Secretary Jacqui Smith says that tough action should be taken against those who pay for sex.
The proposed legislation will make it an offence to buy sex from anyone "controlled for another person's gain".
The only women who will not be covered by it will be those who would work for themselves.
Men using a prostitute despite knowing that she has been trafficked could be prosecuted for rape.
Though the proposal would not impose a complete ban on buying sex, as some campaigners have been demanding, the Government is of the opinion that about 90 per cent of occasions when men visit prostitutes would be covered by the proposed legislation.
The new offence, which will carry a large fine and a criminal record, is expected to be announced in the Queen's Speech on December 3.
Some, however, fear that such a law could drive women underground, thereby making them even more vulnerable. They could also put themselves at risk by being forced to work alone rather than in brothels.
"These plans are not going to make any women's lives safer and will increase the criminalisation and stigma of those working in the sex industry," the Independent quoted a spokeswoman for the English Collective of Prostitutes as saying.
Former Home Office minister Fiona Mactaggart said that the proposals did not go far enough.
"Finland has a similar arrangement where men who pay for sex with prostitutes commit an offence if the woman is trafficked and it hasn't had any prosecutions under it," she told the BBC.
Chris Huhne, Liberal Democrat home affairs spokesman, said: "Any system which cuts out pimps would be welcome, but the difficulty is always in the drafting and application. The Finnish system has not had a great track record."
Dominic Grieve, shadow Home Secretary, said: "The Government's proposals won't protect the most vulnerable - they need to properly enforce the laws we already have."