When the Forsyte Saga was first shown in 1967, its rape scene shocked TV viewers to the core. Now, even a diet including soft porn, naked game shows and incest fails to raise eyebrows.

The timing of Sex On TV, Channel 4's trawl through the seedier areas of the small screen, could hardly be better timed. The first edition returns to 1967, when the rape scene in The Forsyte Saga shocked viewers with its explicit (for then) depiction of the scene in which Soames demanded his marital rights from wife Irene.

It wasn't so much what we saw - little more than a bit of bodice-ripping - but the fact that TV had approached the subject of rape at all.

Even more interesting was the public's reaction then. Sex On TV recalls that a poll showed more people were pro-Soames than pro-Irene. Street interviews found the public calling her a bitch, and saying they felt sorry for him and that he was misunderstood.

The rape scene was "strong stuff in those days", points out presenter David Aaronovitch. Nowadays anything goes. Late night TV features all varieties of sex. Some is contained in the X-rated soft porn movies and series in which Channel 5 specialises. Some comes courtesy of shows like So Graham Norton where you can "watch genital antics not invented in the Fifties, let alone show on TV".

Sex On TV provides a handy reminder of TV's nervousness about handling sex. In the early days of the BBC, the rules about sex were simple - there wasn't any. A 1948 green book laid down what could and couldn't be said and shown. ITV allowed nothing that was in bad taste or offensive to the public.

The publication of Lady Chatterley's Lover in 1960 changed everything. So did exposes about political corruption involving Cabinet ministers and callgirls. Once sex came out of the closet, TV couldn't afford to be left behind.

BBC's That Was The Week That Was was satire, not sex, but challenged Auntie's house rules. Enter clean-up campaigner Mary Whitehouse with her determination to guard the country's morals, whether they wanted it or not.

This provincial housewife couldn't prevent sex slipping under the net in the guise of art or Joan Collins walking naked on London Underground in an episode of the drama series Human Jungle.

As the swinging Sixties got under way - named perhaps because of the amount of dangling private parts aired in the new permissive society - TV was ready to show the real world in Wednesday Plays like Up The Junction.

Programmes seen by 15 million people triggered national discussion about topics such as abortion that were previously taboo. By the mid-1960s viewers could tune in and turn on, aided by changes in the law spearheaded by liberal home secretary Roy Jenkins.

One of the most controversial plays of the time was The Year Of The Sex Olympics by Nigel Kneale, which predicted a TV future of wall-to-wall sex and game shows. That man could make a living as a clairvoyant.

If our island was as squeaky clean as Cliff Richard, foreigners had already discovered sex. Mrs Whitehouse was not about to join them, rejecting an offer to look round a sex shop in Denmark, the most permissive country in the world.

The best we could manage (and very nice it was too) was Honor Blackman as a leather-clad Cathy Gale in The Avengers. This was followed by Diana Rigg in an infamous episode in which she donned a very small outfit, clutching a snake and a whip.

The 1970s brought up the show Germaine Greer describes as the most erotic programme on TV - Top Of The Pops. Presumably she means all that gyrating and pelvic thrusting from Pan's People.

When I first watched A Bouquet Of Barbed Wire in 1976, I had no idea it was such a taboo-breaker with its highly-charged emotional story of father, wife, daughter and her husband climbing aboard a sexual carousel and into each other's beds. These days such storylines are basic fodder for pre-watershed soaps like EastEnders.

The same year, Dennis Potter's play Brimstone And Treacle was banned - and remained unseen for ten years - because of a scene involving the rape of a disabled girl by the devil in human form.

At the same time, I Claudius offered sexual antics in a toga, with Caligula keeping sex in the family. "You could look at breasts and get a lesson in ancient history," notes Aaronovitch.

Interestingly, we also learn that the first lesbian kiss on TV was back in 1974, two decades years before the much-publicised snog between Beth and nanny Margaret in Brookside.

But the programme that changed the nation's attitude to sex was The Naked Civil Servant, the story of Quentin Crisp, self-proclaimed as one of the stately homos of England. John Hurt played him in a drama that was turned down by every film producer and TV company before Jeremy Isaacs at Thames decided to make it.

What was different were not the sex scenes, because there were hardly any, but the attitude to homosexuality. After camp characters presented by the likes of Dick Emery and John Inman, this presented gays in a different, more realistic light.

Not even The Naked Civil Servant could prepare you for this week's The Truth About Gay Sex, basically an illustrated sex manual telling you everything you never knew - and probably didn't want to - about having gay sex.

The scene involving a water melon and an alarming-looking piece of metal apparatus was the most horrifying TV scene involving fruit and veg since a cucumber was used to demonstrate how to put on a condom at the start of the Aids awareness era.

Sex On TV begins on Channel 4 on Tuesday at 10pm.

Published: 04/05/2002