It's 2008 and sex seems to be everywhere. So who holds the line between permissiveness and obscenity? What is obscene these days? And how do those people entrusted to make these calls cope with the harrowing work?
"People think 'what a great job - you sit and watch porn all day'," says Inspector Andy Shortland, who heads the Metropolitan Police's Obscene Publications Squad.
"I think to myself you really would not want to see this stuff. It's not top shelf magazine stuff or soft-core porn which you might hire at Blockbuster. This is really horrible stuff. And when I say that it usually stops them dead.
"But it's just human nature to laugh about it," he adds.
The squad, the only one of its type in the country, consists of 12 officers, including one woman. Its role is threefold - to monitor what is on sale at licensed sex shops, to target and convict pedlars of illegal pornography and to advise other law enforcement agencies.
 |   Lady Chatterley's Lover was once considered obscene but certainly wouldn't be now  Inspector Andy Shortland |
But what, in these more permissive times, is considered obscene?
During the trial of American pornographer Larry Flynt in the 1970s, his lawyer Louis Sirkin observed: "One man's obscenity is another man's art." In England, the law is governed by a piece of legislation almost half-a-century old - the 1959 Obscene Publications Act.
It defines obscenity as "content whose effect will tend to deprave and corrupt those likely to read, see or hear" it.
It helpfully adds: "This could include images of extreme sexual activity such as bestiality, necrophilia, rape or torture."
Insp Shortland says: "What was socially unacceptable 10 or 20 years ago may be acceptable now. There is a moving line. For example Lady Chatterley's Lover was once considered obscene but certainly wouldn't be now.
"But bestiality, necrophilia, rape and torture would still be considered obscene," he says, as would depictions of sexual gratification through lavatorial functions.
The Obscene Publications Squad works closely with the British Board of Film Classification (BBFC), which is responsible for censoring and labelling all films released in the UK, whether they are movies for the cinema, videos and DVDs for the regular retail market or specialist sex shop material.
Straw dogs release
Rape and torture scenes - sometimes in mainstream movies - have been problematic for both the police and the BBFC.
 In America Larry Flynt fought a long fight to defend pornography |
"There is quite a high threshold," says Insp Shortland. "Some caning films can have bad injuries - which are not life-threatening - and that is considered to be obscene. Some rape films are 'fake' with actors portraying rape. It is quite a difficult line to judge."
The case of the 1971 film Straw Dogs, directed by Sam Peckinpah and starring Dustin Hoffman and Susan George, is well known to many film buffs. Originally banned because of a horrific rape depiction, the BBFC passed a different edit of the film in 2002 - which included the scene.
It would be wrong to assume the decision was due to greater tolerance of sexual violence, says the BBFC's senior examiner, Murray Perkins. Far from it.
"Sexual violence is one of the areas where our position which has not changed much over the years," says Mr Perkins. "It's still one of our main concerns. The mixing of sex and violence is something which concerns people and rightly so.
"The makers of Straw Dogs had done their own edit and in the process the film gave the impression that the female character enjoyed the rape. In the full uncut version, that was balanced by another event in the film which gave it context and that was why we were able to pass it."
'They want to be here'
Viewing the scene is deeply unpleasant even for someone who appreciates the film's artistic merit. So how do those who must watch this sort of material for hours each week cope?
Insp Shortland admits it can be tough on his team, but says there are safeguards in place to ensure officers' mental health is not endangered.
"They will not be monitored all the time. If there is one officer dealing with all the material then they will be offered open access to the occupational health department.
"If someone comes to me and says 'I can't take any more of this' I will listen to that. But at the end of the day they are here because they want to be here. They work as a team and are quite open about what they can and can't manage to watch. Each person knows their limit and what they feel less comfortable with."
The workload for Mr Perkins and his fellow examiners at the BBFC is less gruelling.
"Some people think it sounds like the best job in the world," says Mr Perkins. "But the way we do the viewing you are disengaged to a certain extent because you are making notes and are hyper-sensitive to the language and the context. You are viewing it as a job and you've got to be mindful of policy, guidelines and public expectation."
But do examiners risk becoming desensitised?
Legal defence
"If you see something which is raw, misogynistic, aggressive and violent you don't become desensitised to it. What is not right is never right."
 The film Nine Songs, which came out in 2004, contained real sex but was uncut |
"The majority of the cuts were little sections rather than a whole scene. It may be strong abuse, violent behaviour, temporary strangling, or it may be a reference to under-age sex," Mr Perkins says.
While an R18 rating is not a legal defence for a pornographer, it would be very unlikely for the Obscene Publications Squad to take action over a film passed by the BBFC.
Insp Shortland says they have had very few trials as few pornographers are willing to pin their hopes on 12 jurors. And he thinks pushing smut has become too easy nowadays. "You just get a master DVD burner and make thousands of copies in your attic. The overheads are very low."
Back at the BBFC, there have been glimpses of more permissiveness in what it's willing to license for mainstream distribution. Films given a regular 18 certificate are only supposed to contain "simulated sex" but there are exceptions, such as Michael Winterbottom's controversial 2004 movie Nine Songs.
The censors judged it to be "exceptionally justified by the context of the film". Surprisingly, perhaps, the only DVD rejected outright by the BBFC was a box set of season two of the TV series Weeds. That was not because of sex or violence, but a scene was seen as promoting drug use.
