After enduring freezing temperatures, shifting ice and the threat of polar bear attack, a daring dad has completed one of the world's most demanding marathons.

Mark Clifford pushed himself to the limit in the North Pole Marathon, running through a blizzard in cumbersome snow shoes over mile upon mile of cracked ice and soft snow.

The 44-year-old raised an incredible £40,000 for charity, after enduring temperatures between -10C and -23C.

Mark flew on to the Polar ice at Camp Borneo in a twin propeller Russian transport plane from Spitsbergen, Norway, while wife Debbie and 16-year-old daughter Floss waited anxiously at home in Micklethwaite near Bingley.

"The Pole was thrilling and spellbinding because it was so massive and quiet, but the race was harder than I'd thought. Half of it was on a field of flat sheet ice, so it was nice and easy.

"The other half was the opposite. For 14 or 15 miles you would put your foot down on snow and it would land OK or disappear two and a half feet into a hole.

"We were advised because the ice was cracking to stay within the specially marked out course. Polar bears had been spotted in the area around the course previously, and the Russians had guns just in case."

Before the race, Mark and the 53 other runners had settled down in £1,000 per night accommodation run by a Russian crew.

"It's not what you'd expect. Just a tent and camp bed with sleeping bag and diesel fumes pumping in from the heater designed to keep you warm. The alternative was being out on the ice, so it was relative luxury.

"A problem was that the Russians ran out of fresh water, so they were trying to melt snow. They weren't ready for the amount of water 50 people will get through, even at the Pole. The snow is sea water, so drinking salt water was not in the least bit pleasant."

Despite the punishing setting, Mark said he coped relatively well, only suffering close to the 21-mile mark.

"My feet were really cold, almost freezing from stepping through the deep snow. It got pretty unbearable so I had to stop, dry my feet and change shoes and socks."

Mark ran with his friend, David Donnell-Jones, from Warrington. The pair finished joint 35th, with a time of eight hours, 56 minutes, 33 seconds.

"To keep morale up we had long chats. In one we built the menu of the perfect meal, which included pasta and a pizza with pepperoni. Then we created a polar bear evasion plan. It was pretty silly, but it kept us going."

Mark raised £20,000 for Hopes and Homes for Children, a charity caring for children in Eastern Europe and Africa orphaned or abandoned through war, poverty or HIV/Aids.

Leeds wealth management company St James's Place, where Mark works as sales executive director, will match the total for its charitable St James's Place Foundation.

Mark is no stranger to endurance, having already competed in the Sahara Desert Marathon des Sables, the Kilimanjaro Marathon and the highest marathon in the world, the Everest Marathon.

e-mail: jonathan.walton@bradford.newsquest.co.uk