Blue Peter's Helen Skelton reaches South Pole

Blue Peter presenter Helen Skelton has completed a 500-mile (800km) trek to the South Pole - on skis, kite skis and an ice bike.

The TV star battled for 18 days through severe snow storms, temperatures as low as -48C and a bad bout of dehydration.

She said her body hurt in countless places, but finishing the challenge for Sport Relief felt "incredible".

The 28-year-old also set a new world record for the fastest 100km by kite ski - in seven hours 28 minutes.

"The environment is so harsh and on a day when you can get sunburn, you can also get frostbite," she said.

'Pure grit'

"I could feel my ears burning through my helmet because of the wind.

"This has been a massive adventure and at times it felt like it was never going to end.

"My body hurts in so many different places, mentally I'm exhausted and I've only washed once in the last 30 days, so to be finally standing at the Pole feels incredible."

Skelton became the first person to use a bike - with specially adapted wide tyres - as part of an expedition to the Pole.

She covered 329 miles by kite ski, 103 by bike, and 68 by cross-country ski.

She pulled a sledge containing her supplies that weighed a total of 82kg (13 stone).

The adventurer suffered numerous blisters, a hacking cough, and ongoing stomach troubles during the trek with Norwegian explorer Niklas Norman, a small BBC team and a logistics crew.

British explorer Sir Ranulph Fiennes said: "I take my hat off to Helen Skelton. I have to admit when she first told me that she was going to cycle part of the way to the South Pole, I laughed.

"But through pure grit and determination she has got there and shown that, yes, you can use a bike to reach the Pole. Her incredible efforts are a great example of willpower."

Her latest adventure follows her successful high-wire walk between the chimneys of Battersea Power Station, in London, and a solo kayak voyage down the length of the Amazon.

To find out more about Sport Relief 2012 and enter a Sport Relief Mile go to bbc.co.uk/sportrelief

Helen's Polar Challenge for Sport Relief will be shown in a special nine-week series on Blue Peter starting on 23 January at 1630 GMT on BBC One.