Tribe (BBC2, 9pm) Ultimate White Water (BBC1, 9pm)

ONE of the current trends in cinema is what's been termed "torture porn" - horror films in which victims are shown being maimed and mutilated for our pleasure by some usually-unseen sadistic torturer.

Some sadistic soul at the BBC obviously wants to give us the small screen version as hardly a night goes by without a celebrity or explorer being subjected to all manner of unspeakable horrors.

After sending a Watchdog presenter climbing last week, Ultimate Wild Water literally throws newsreader Kate Silverton in at the deep end and she almost drowns between her panic attacks.

Or, over on BBC2, you can see a professional extreme adventurer - explorer Bruce Parry in Tribe - being subjected to four rituals which the Matis people believe will make him a better hunter.

Being whipped, having tree sap dropped into his eyes and being beaten with leaves prove child's play compared to having frog poison introduced into his blood stream. It sends him woozie, makes him light-headed and when he's told "vomit down here", you know it's not going to be pleasant.

After a major evacuation of his bowels (fortunately that happens off camera), he feels a new man. Viewers, on the other hand, may still have their head in a bucket.

First, an apology to Kate Silverton for calling her Kate Thornton in this column last week. At least I didn't confuse her with Kate Humble (who is sent pot-holing on Friday). It obviously helps to get a job at the BBC if your name is Kate.

In North Cornwall, Kate Silverton's wild water guide, former Royal Marine Patrick Winterton, is assessing her strengths and weaknesses by taking her out to sea - a pretty stormy one - and making her swim back to shore.

She manages to reach the beach with a cry of "glug, glug... so horrible". The rest doesn't make much sense as she's hyperventilating, having panicked at being crushed beneath the waves. So much for trying to overcome her childhood fear of the open sea.

There are other BBC newsreaders I would cheerfully push into the deep end. Silverton isn't one of them, so I can't help but feel sorry for her as she tackles stretches of the most extreme water in Britain.

"I'm out of my depth and can feel the panic rising," is a typical comment as she undergoes kayak training and jumps into the coldest water in England in the Lake District.

"Increasingly petrified" is another phrase that passes her lips when she's not swall-owing water.

Her final solo challenge is a bitch. Or rather, The Bitches - a stretch of white water and rocks off the Welsh coast. It's a daunting task to do in a kayak and even Winterton wonders if it's too much for her.

Bruce Parry, as previous series of Tribe have shown, is game for anything if it helps him get to know and understand the remote tribes with whom he goes to live for weeks on end.

He's not welcomed with open arms by the Matis in the Amazon rainforest because they've had previous, unhappy experiences with outsiders. Uncontacted until the 1970s, the arrival of "foreigners" led to the tribe almost being wiped out by western diseases. They tell Parry that the last film crew wanted them to take off their clothes and prance around naked. He has to assure them he wants to show them as they are and how they're coping with the modern world.

He's given a blowpipe of his own so he can kill a monkey for the women to cook. The ladies seem to like this stranger. They sit around complaining about the young menfolk who play football, something they've picked up from outsiders, instead of providing food.

The Matis have an uneasy relationship with what we call civilisation. One of the young men is a student in town but doesn't go out when he stays there because of the drugs and violence.

There's no going back for the tribe. They live in a protected area but the influence of the modern world is unavoidable. As Parry says, they were happier before contact but can never go back to the way they were.