By Dominic Casciani
BBC News home affairs reporter
The act of exchanging money for sex is not in itself illegal
What is the current law on prostitution?
The laws around prostitution in England and Wales are far from straight-forward. The act of prostitution is not in itself illegal - but a string of laws criminalises activities around it. Under the Sexual Offences Act 2003, it is an offence to cause or incite prostitution or control it for personal gain.
The 1956 Sexual Offences Act bans running a brothel and it's against the law to loiter or solicit sex on the street. Kerb-crawling is also banned, providing it can be shown the individual was causing a persistent annoyance.
Adverts placed in phone boxes have been banned since 2001. Human trafficking, a component of modern prostitution, is also covered by the law. There are also general laws on public nuisance and decency which can be used to target the sex trade.
The law in Scotland is broadly similar but was recently toughened up around kerb crawling and seeking the services of a prostitute.
What does the law mean by a brothel?
If more than one person (the law is gender neutral) is available in a premises for paid sex, then that is a brothel. However, if one woman works alone, she is not keeping a brothel.
How could the law soon change?
Home Secretary Jacqui Smith has announced England and Wales will fall in line with Scotland by removing a need for persistent nuisance in the kerb crawling offence - making it easier to prosecute.
But she is also wants England and Wales go further, by criminalising paying for sex with someone who is "controlled for another person's gain".
The English Collective of Prostitutes says it sees no reason why consenting sex between adults should be criminalised just because one party pays.
This will be a "strict liability" offence, and ignorance of the circumstances will be no defence in court.
An example: A man approaches a woman who is selling sex. She tells him that she is not being controlled. She gets in his car. Police charge the man with paying for sex. He insists he had no idea she had a pimp - but he still ends up in court and is found guilty. In other words, if you go to a prostitute, it doesn't matter whether or not you know that she is being controlled - you will be charged.
The law will cover activity controlled by a pimp - examples would include a woman who is addicted to drugs and is being offered for sex to clear her debt with her dealer.
Police will also be given greater powers to close brothels - a law which is expected to also be introduced in Scotland.
Finally, licensing rules will change to subject lapdancing and strip clubs to the same regime as sex shops in an effort to halt their unchecked expansion in city centres.
Why hasn't the government brought in an outright ban on paying for sex?
Ms Smith told the BBC ministers had considered a ban but had ruled it out as there was no public support for such a move.
Instead, she said the government's efforts would be focused on reducing demand for trafficked women, who were "effectively held as slaves", and there would be a marketing campaign aimed at men who used prostitutes.
What about naming and shaming?
There's talk of some form of public naming and shaming of kerb crawlers - but it's unclear what this means. The London council of Lambeth names convicted drug dealers on its website and officials are considering extending the idea to kerb crawlers. But that's not quite the same as plastering their faces on lamp posts.
Under the government's plans, all those convicted of kerb crawling, including first-time offenders, could get a fine and a criminal record.
Are there critics?
The English Collective of Prostitutes, which campaigns on the law, opposes the moves, saying it will drive the trade further underground rather than making women safer. It says it sees no reason why consenting sex between adults should be criminalised just because one party pays.
It argues that women who want to work together in the sex business should be allowed to do so in safety - and the men who buy their services should not be turned into criminals.
So what's the idea behind the changes?
The Home Office has had a long and difficult debate over the past four years over prostitution laws. In 2004 if floated a number of radical solutions including creating "managed areas", regulating off-street prostitution and licensing brothels.
All of these were discounted in 2006 after ministers decided to target those causing the harm and attempt to do more to get people out of the sex trade. So these new changes are geared towards cracking down on those who buy sex or control its sale, and the impact they have on the community, rather than those who offer it.
What steps have been taken to help women in prostitution?
A recent report into Ipswich, where Steve Wright murdered five women in 2006, says that intensive support for prostitutes helps protect the women and get them off the streets. The five-year strategy includes close contact with social services, health services, housing and drug specialists.
Does any other country ban paying for sex?
The idea of criminalising paying for sex gained currency because of the experience of Sweden. It banned paying for sex in any circumstances which supporters say made it harder for customers to openly seek out prostitutes.
But critics say that this approach takes up a lot of police investigatory time - and the reality is that Sweden has far smaller prostitution problem than the UK.