What you get up to in the bedroom, or elsewhere, has never been entirely your business. Soon, a raft of new sex laws will be enacted. So what will be allowed and outlawed?
By the yardstick of the English poet Philip Larkin, the sexual revolution is marking its 40th birthday this year.
"Sexual intercourse," Larkin once famously declared in one of his verses, "began in 1963 (Which was rather late for me)".
The broadminded, however, would argue that any genuine breakthrough in sexual attitudes never got off the starting blocks.
Many of Britain's sex laws are a throwback to another era. Even the wording can read like something out of a Dickens novel. For example, the man in the dirty old raincoat who bares all to a passer-by, might expect to be charged with "exposing the person".
The term features in the Vagrancy Act 1824 and the Town Police Clauses Act 1847 - both of which are relied on to prosecute flashers, along with the common law offence of "outraging public decency".
"The law on sex offences is largely recognised as archaic, incoherent and discriminatory," said Home Secretary David Blunkett recently.
That's about to change. With the new Sexual Offences Bill, the government has come up with a brand new set of sex rules that are destined to overturn many of the old laws. So what will and won't be allowed in 21st Century Britain?
HOMOSEXUAL GROUP SEX
SEXUAL OFFENCES BILL
The bill proposes tougher laws on rape and child sex abuse
It also repeals offences such as buggery and gross indecency
And tightens up on non-consensual sex of all kinds
There's nothing to stop heterosexual orgies, but take women out of the equation and you've currently got yourself a law suit. The issue was highlighted three years ago when the European Court overturned a conviction in the so-called ADT case - named after the initials of the three men involved. The case became a cause celebre for many gays after police in Yorkshire prosecuted a man after they were handed a sex video filmed at his home of the accused and two male friends. The new law takes a "gender neutral" approach to sex, granting equal rights to homosexuals and heterosexuals.
The tendency has sometimes been to dismiss flashers as "dirty old men"; sad and harmless. But the new law comes down hard on the raincoat brigade, threatening a prison term of up to two years. Research has shown a link between flashing and more serious sexual crime. However, it shouldn't stop naturists doing what comes naturally. MPs have responded to naturists' concerns that by going naked they might fall foul of the new law, by amending the bill. Streakers are also protected, and should continue to be treated as a social nuisance rather than sexual offenders. Under the new bill, the (relatively few) women who indecently expose themselves will be punished as harshly as the men.
Indecent exposure it ain't
The days of the old "peeping Tom" are gone. Voyeurism today is about miniature video cameras and posting films on the net. And like indecent exposure, there is evidence to link the practise of secretly watching someone with more serious offences (one study found 14% of child molesters and 20% of rapists had "committed voyeurism"). In the past, there has been a tendency to regard the practice as a nuisance rather than a crime. The proposed new law threatens a two-year sentence for anyone who views a film knowing the subject had not given consent.
The proposals represent a softening attitude to so-called "zoophiles", who risk a life sentence under the terms of the current law. It ties into the bill's general theme of "consent" - that fundamentally all sexual activity should be mutually agreed. But again, research has shown a link between abuse of animals and abuse of children. Nevertheless, the proposal has drawn criticism from libertarians, such as Francis Bennion, a barrister and author of The Sex Code, a moral guide to sex. He argues that since the act is recognised to be "profoundly disturbed behaviour" zoophiles should be sent not to prison, but the psychiatrist's couch.
Many people will be alarmed that sex with dead people is not currently a crime. But that's about to change even though critics argue cases of necrophilia are rare and this is simply an opportunity for the government to reinforce its high moral authority. Nevertheless, offenders can expect anything up to two years in prison.
SEX IN A PUBLIC PLACE
A clutch of laws already exists to prohibit sex in public, but the government has backed down on a new overarching law, which would have banned outdoor love making in private grounds which were overlooked. According to the government's consultation documentation, there was never any attempt to "criminalise sexual activity that takes place outdoors but in an isolated place where one would reasonably expect not to be observed".