The Secret Diary Of A Call Girl (ITV2, 10pm) Meet The Natives (C4, 9pm) The Whistleblowers (ITV1, 9pm)

SOME programmes make you laugh, others make you cry. Some programmes entertain, others annoy. Then there's The Secret Diary Of A Call Girl, which just makes you feel like a bit of a perv.

Should I really be watching a girl young enough to be my grand-daughter romping around in her undies, administering oral sex and sitting astride a naked man on all fours to ride him round the room like a horse?

It's a dirty job but somebody has to do it. I get paid (not very much, admittedly) to watch Billie Piper prancing around in skimpy lingerie and having pretend sex.

Undoubtedly, ITV2 will be very pleased with the ratings. Sex sells. If you want to draw attention to your channel, bare bits and smutty talk are a surefire winner.

Unfortunately, The Secret Diary Of A Call Girl lacks anything else. This is all right as far as it goes, which is quite a long way even for a post-watershed slot.

Belle de Jour is upfront about her profession. "The first thing you should know about me is that I'm a whore," she tells us. "Escort, hooker, prostitute, whore - I don't mind what you call me that's just semantics," our hostess adds, showing she knows a few big words as well as many big boys.

She charges by the hour and charges a lot. This is obvious by her plush surroundings and the quality of her undies. We have much opportunity to examine her undies. I must stop this, I'm beginning to sound like pervert again. She's a simple working girl. Unlike most of us, she works flat on her back or her knees, depending on the service she's providing. She loves sex and she loves money, so she's found the perfect job.

Billie Piper is very good. I'd ring her Belle any time. Ding dong, as Leslie Phillips would say. She looks fabulous. She performs the sex scenes with gusto, proving that he who pays the Piper calls the tune. Cherie Lunghi pops in occasionally as her boss. Various actors bare their bums.

And there you have it - a blow-by-blow account of what a call girl does. It's not so much a programme as a commercial for the sex industry.

Meet The Natives would seem a novel idea if five hadn't already done a series in which tribesmen - those haven't been visited by Tribe's Bruce Parry - experience life in England. The C4 natives are a nice bunch from a tropical island in the middle of the South Pacific. Life is pretty relaxed on their island. They tend their plants, look after their pigs and tell each other stories. They swap their penis sheaths - something Belle might like to incorporate in her fun and games - for underpants to stay on a pig farm in Norfolk.

The pigs are bigger and fatter than those back home. The tribesmen don't understand artificial insemination. "How will they get satisfied?" asks the chief.

They also believe sex among pigs should be done in private, but accept the invitation to have a go at getting a pig pregnant - although I'd question the value of travelling halfway round the world in order to shove a tube of sperm up a pig's oriface.

What the natives really want is meet Prince Philip and take him home with them. They believe he's the son of their god. He's a spirit but has taken on the physical form of a man in England.

A man in his underpants is running down the street. Not a scene from The Secret Diary Of A Call Girl or even Meet The Natives, but ITV1's new thriller series, The Whistleblowers. He's a suspected terrorist who's escaped from the house where the intelligence services are torturing him by playing episodes of El Dorado round the clock.

Richard Coyle and Indira Varma are lawyers with a conscience quitting their jobs to help people who blow the whistle on injustices in society.

In the real world, they'd join the "disappeared" before they had time to dial 999. Here, through a series of coincidences, they save the day, or, as their friend says, "do a good deed in a bad world".