Arctic Explorers

Imagine being stuck on a disintegrating ice floe in temperatures of minus 40 degrees.

You're running out of food and fuel and bad weather is stopping supplies getting through to you by air.

You've been stranded for three days in a tent with your companions - one of whom has got a frostbitten toe - and it's still two months' trek until you reach the North Pole.

That was roughly the situation of three British explorers who've been sponsored to travel to the Pole by the Catlin Arctic Survey. They're measuring the thickness of the Arctic sea ice as they go.

Pen Hadow, Martin Hadley and Ann Daniels were dropped in the middle of an icy wilderness nearly three weeks ago.

The past few days have been particularly gruelling - but the flight with their new supplies has finally got through.

We spoke to Pen Hadow on his satphone - in the middle of the night - in the middle of the Arctic.