3.1 Money laundering
Money Laundering was made illegal by the Proceeds of Crime Act (2002). If you are an escort running an entirely legal business then you are unlikely to be caught by it; if you run a brothel it definitely could affect you. And since the punishment for money laundering is up to 14 years imprisonment plus an unlimited fine it's probably as well to know something about it.
This section is all about how the law affects you. If you want to know how it affects your accountant there's a separate section on Accountants & Money Laundering.
The three Money Laundering offences are straightforward enough. A person commits a money laundering offence if he (or she):
graphic  conceals, disguises, converts or transfers criminal property, or removes criminal property from England and Wales, or from Scotland or from Northern Ireland (section 327)
graphic  enters into or becomes concerned in an arrangement which he or she knows or suspects facilitates (by whatever means) the acquisition, retention, use or control of criminal property by or on behalf of another person (section 328)
graphic  acquires, uses or has possession of criminal property except where adequate consideration was given for the property (section 329)
Criminal property is any property that the alleged offender knows or suspects is the benefit from a crime. And a crime for these purposes is any criminal offence committed in the UK, as well as anything done overseas that would have been a crime if it was taken place in the UK.
So for you to be caught by the money laundering offences there need to be three things:
First there needs to be a crime - prostitution is not a crime although some of the activities surrounding it are
Secondly there needs to be criminal property - most crimes (other than pure violence, motoring offences and possibly bigamy) produce a benefit to the criminal whether it's cash or property of some kind
Finally, you need to be involved in concealing, disguising, converting or removing criminal property; or enter into an arrangement to help someone else acquire, retain, use or control criminal property; or acquire, use or possess criminal property yourself.
Some examples
graphic  You are an independent escort working on your own. Prostitution is not illegal so there is no crime and any money you receive for your services isn't criminal property. No problem.
graphic  You manage a brothel and make money from the prostitutes who work there. Brothel management is a crime and the money you receive is the proceeds of crime. Big problem.
graphic  You work in a sauna or brothel but are not involved in managing or controlling it. The money you receive from your punters is not criminal property. However when you pay over a percentage to the brothel-keeper are you becoming involved in an arrangement that facilitates his acquisition of criminal property? Possibly: it wasn't criminal property when you had it but it is when the brothel-keeper gets his hands on it.
graphic  You run an escort agency. Is that a crime? I am not a lawyer, but there is some suggestion that it is a crime, in which case you may be caught by the money laundering offences.
graphic  You are an escort getting work through an agency. Again there's no problem when you get paid by your client but it's not at all clear whether paying the agency their fee creates a problem. You might have a good case for arguing that you did not 'know or suspect' it was criminal property.
graphic  You fraudulently (as opposed to negligently) evade tax. That is a crime and the tax you haven't paid is classified as the proceeds of crime. In theory you could be prosecuted for tax evasion and money laundering, but in practice HMRC will generally use civil means to extract the lost tax from you - with interest and penalties.
graphic  A client hands you the envelope and then tells you he held up a petrol station at knife point so he could pay you. You are clearly receiving the proceeds of a crime. However you should be able to argue that you are getting no more than adequate payment for your time and companionship. So probably no problem. 
graphic  You run a perfectly legal brothel in Australia and decide to retire to the UK bringing with you your accumulated profits with which you buy a maisonette in Rotherham. You are guilty of money laundering because the money arose from activities carried out overseas which would have been a crime if you had done them here.
How the authorities monitor money laundering
Sitting underneath the Proceeds of Crime Act is a document called the Money Laundering Regulations. They've recently been revised and a new version came into force on 15 December 2007. The regulations apply to everybody working in the 'regulated sector' which is principally lawyers, banks, estate agents, casinos, bureau de change, High Value Dealers (HVD's - businesses receiving more than 15,000 Euros in cash from an individual) and accountants.
Incidentally even if an escort receives over £10,000 in cash (which is roughly €15,000) from a client she won't be treated as an HVD because she is supplying services and not goods. Unless of course you get lucky and a punter buys 10 grand's worth of used panties.
The Money Laundering Regulations require regulated businesses to have procedures for verifying the identity of their customers. They also have to make a report to SOCA (the Serious Organised Crime Agency) if they know or suspect that money laundering has taken place. At least one solicitor has already gone to prison for failing to report his suspicions, so it's not something that regulated businesses can afford to ignore.
How the Money Laundering provisions are being used
graphic  There are increasing signs that the authorities are charging people with money laundering offences particularly in relation to drug and immigration crime. There have also been a lot of raids on brothels, particularly (and quite rightly in my opinion) on establishments where they suspect drug dealing, human trafficking, forced prostitution or underage girls.
Flats where two girls choose to work together for safety seem to be ignored unless they are causing a nuisance.
There is also no sign that HMRC are using the money laundering rules to combat tax evasion: probably because they have much more effective ways of dealing with that.