Living On The Edge: Blood In The Sea (Channel 5, 7pm)

CHRIS Terrill is clearly up for a challenge. The film-maker was in his mid-fifties when he trained as a Royal Marines Commando so he would be able to follow new recruits on the frontline in Afghanistan for an acclaimed 2007 ITV documentary series.

Then last year, he visited some of the most inhospitable places on earth for the programmes Surviving the Arctic and Surviving the Desert.

"My main interest is in what makes people and communities tick, wherever they might live on the planet. I see my job as a filmmaker is to help cast light on the human condition and to help us all understand people outside our own terms of reference," he says.

This time, Terrill s setting out to find out how people endure in regions where nature is at its most ferocious, a journey that begins in Mauritania. The African country is arguably most famous for its vast deserts and nomadic people, but it also has a long tradition of fishing - its Atlantic coast borders some of the richest grounds in the world. But waters can also be treacherous.

Terrill plans to take to the waves with a Mauritanian crew to learn more about the dangers involved, but he's not the only one putting out to sea for the first time.

The fishermen speak a variety of languages, and the only person Terrill has found who can interpret them all is Ahmed Taleb, a nomad who is more used to life in the desert. He's never been on any kind of boat before, so how will he find taking to the crashing waves on a traditional open wooden ship?

Taleb and Terrill later travel from Nouadhibou in the far north to the capital Nouakchott in the south, where they see a thousand boats, all attempting to make it through the angry surf.

"I would always recommend travel to exotic places, not just to see incredible landscapes but to meet different people and experience new cultures - it's much better for the soul."

Posh Pawn (Channel 4, 8pm)

THIS series frequently felt more like an edition of Four Rooms or The Antiques Roadshow than Benefits Street, largely because the objects on display are so fascinating. This week, Kristin's gem-valuation skills are put to the test when she's faced with a piece of jade that could be worth in excess of £30,000.

Meanwhile, a 47-year-old woman hopes diamonds really are a girl's (and a father's) best friend, as she tries pawn her mother's ring to raise funds to stop her dad's house subsiding.

Weybridge manager Jamo gets his hands on a classic 1930s motor as part of his first car assignment, and a young couple have come up with an unusual way to pay for their wedding - selling off a limited edition Philip Treacy handbag.

The Apprentice (BBC1, 9pm)

THIS week the candidates tackle a challenge they should have known was coming the moment they applied - it's the buying task, where they are given a list of nine items they have to acquire as cheaply as possible.

Unlike in previous years, where the teams spent half the episode trying to work out what exactly “nigella seeds" were, the list is made up of items that have featured during the show's history, including such greatest Apprentice hits as oud oil, and a kosher chicken, which caused a lot of trouble in the fourth series.

But even this prior knowledge won't be much help if the teams don't have the necessary bargaining skills.