Ahh, Ed got there first. Good stuff.

it kind of is legal, isnt it? porn is exchange of money for sex.

http://www.sfc.org.uk/sexlaws.html

It has always been legal to shoot hardcore, and edit pornographic films in the UK. The restrictions are on selling and distributing it. Illegal acts, such as actual rape, strong S/M, or sex with children or animals would, however, make filming or photography of them illegal.

NO WAY

BEING A PROSTITUTE is legal - both hetero and gay, so long as he/she is 18 or over. The problem for prostitutes is that most things they need to do to earn a living are illegal, ie:-
• explicitly advertising their services - although newspapers now happily take "massage" adverts and many prostitutes now advertise on the Internet.
• soliciting in the street - which can mean as little as walking along with a condom in your handbag - is outlawed by the Street Offences Act 1959. Street walkers can also be prosecuted under the Vagrancy Act 1824. Men can be prosecuted for "importuning", whereas women cannot (Sexual Offences Act 2003).
• hanging out in the street - some street workers are being prosecuted for public order offences and receive ASBOs - Anti Social Behaviour Orders. Local authorities use ASBOs out of context to ban prostitutes from working in their area. There is also the possibility of prosecution for "outraging public decency" (Common Law). This has been used against "back-ally" sex workers including those who give quick hand jobs.
• cause alarm, distress or harassment - which could be from just "being a prostitute" - under the Public Order Act 1986.
• The Licensing Act 1964 prohibits landlords serving a prostitute and the Town Police Clause Act of 1847 criminalises selling refreshments to sex workers sitting together. The worry about the latter supposedly defunct Act is that it could criminalise health workers and volunteers who run drop-in centres.
• prostitutes paying men to help them (although you may be allowed to employ a female "maid"). The Sexual Offences Acts 1956 and 2003 criminalise men for living off immoral earnings, and men and women for "controlling prostitutes".
• working together in a flat, in a brothel, massage parlour or for an agency is illegal under the Disorderly Houses Act 1751 and the Sexual Offences Acts. It is normally tolerated in practice, so long as there are no drugs or underage people involved, and the neighbours have not complained.
• renting a flat is often difficult, as standard leases forbid the premeses to be used for "immoral purposes" and this means that a prostitute risks having her tenancy terminated.
• as they are providing a service, prostitutes should strictly speaking charge VAT if their earnings are over and above the relevant limit. But clients don't want to be identified, let alone be handed a VAT invoice. Prostitutes fear the Inland Revenue making extortionate income tax assessments (eg the Lindi St Clair case). As prostitution iteself is lawful, the income is taxable. Most sex workers thus make the choice to either (a) work undercover, stating another profession on their tax form. The Inland Revenue really don't care what you call yourself, so long as you pay your tax. or (b) work outside the tax system, in the black economy. To avoid suspicion and keep their National Insurance up-to-date, many sign on at the Job Centre for six months after which Jobseekers Allowance ends.
• sex workers have few legal rights and little protection from the law. They find it very difficult to get police protection or to take a case to court against a violent client for assault and there are many violent clients. Technically, if a client refuses to pay, that is rape because consent was a condition of payment. Juries, however, rarely convict a man of raping a prostitute.