Harriet Harman will today step up her drive to make buying sex illegal when she releases new figures showing that more than half of men and women support the move if it will reduce people-trafficking for sexual exploitation.
Labour's deputy leader, the minister for women and equality, will also highlight cultural double standards after some respondents, particularly older men, condoned buying sex but condemned those who sell it.
A Home Office-led review into the demand for prostitution, due to report this year, is looking at whether ministers should make it illegal to pay for sex. The review is looking at a range of options to curb demand, but the Home Office minister, Vernon Coaker, has given a broad hint he will back criminalising the purchase of sex if there is a sign of a national consensus on the issue.
The findings of the government-commissioned survey are likely to give ministers greater confidence in introducing the measure. At present the law makes it illegal to sell sex, but ministers including Coaker have visited Sweden to see if tougher laws, including banning the purchase of sex, can work.
Harman has the backing of a number of prominent ministers, including the solicitor general, Vera Baird, and the attorney general, Lady Scotland.
Harman claimed some people in the survey showed "double standards", indicating that they were relaxed about the principle of paying for sex but would be deeply ashamed if a female relative was working as a prostitute.
The Ipsos-Mori poll, conducted in July and August, showed that more than half of men and women (58%) support making it illegal to pay for sex if it will help reduce the numbers of women and children being trafficked into the UK for sexual exploitation.
The research also found divergent attitudes between women and men. A clear majority of women found both paying for sex and selling it unacceptable (61% and 65% respectively), but men were much more equivocal, with just 42% and 40% respectively finding it unacceptable.
More than half of those questioned (60%) from both genders would feel ashamed if they found out a family member was working as a prostitute. But men were more likely to find it unacceptable for a female relative to sell sex, while being relaxed about a male relative paying for it.
This difference was most stark among men over 55, who were the most accepting of buying sex in general, but just 21% of whom thought it acceptable for a female relative to sell sex.
Young people were more likely than older people to find paying for sex and selling sex unacceptable (64% and 69% respectively).
Harman said: "Our survey suggests that there are double standards out there: the overwhelming majority of those people who said they thought selling sex was a reasonable choice also said they would find it unacceptable if a family member was working as a prostitute.
"While the majority of men and women agree that paying for sex should be made illegal if it will help stop the trafficking of women for sexual exploitation, women and young people are much more likely to find the whole idea of paying for sex unacceptable. We know that paying for sex fuels the demand for trafficked women and children, but we can't talk about tackling demand without challenging cultural attitudes more widely."
Harman has been allowed to express her personal view that buying sex should be made illegal before the government review has been completed.