Cross-Canada runner Jamie McDonald: 'It's a suicide mission'
If he completes his 5,000-mile run across Canada, 27-year-old Jamie McDonald from Gloucester will be the first person ever to do so unaided. But, three-quarters of the way through and already fearing he will lose his nose to frostbite, will he actually complete the challenge?
"It's been a once-in-a-lifetime journey - it's the best thing I've ever done," says Mr McDonald.
"But it comes with a lot of hardship and lately it's become really tough."
He had hoped to finish the challenge, running from Canada's east coast to the west - the equivalent of about 200 marathons - in time for Christmas.
But a series of setbacks, including injuries and bad weather, means he still has the equivalent of about 30 marathons to go - over harsh terrain and freezing temperatures.
He is now likely to finish in mid-January.
The delays have meant he's about to tackle the Rocky Mountains in the depths of the Canadian winter.
"I ran in minus 40 degrees the other day, I've also got chronic tendonitis, and I got frostbite on my nose.
"It went brown. I thought I was going to lose it."
Mr McDonald has had no special training for the challenge, having never even run a single marathon before.
Since he began at St John's in Newfoundland on 9 March he has run most of the way dressed as comic book superhero The Flash.
He pushes a buggy carrying his belongings as he goes.
Having gained publicity on Canadian television he has been staying with strangers in their homes, as people have offered food and shelter after becoming aware of his goal.
But the next part of the route passes through part of the country where homes are scarce.
"I stayed at a British Army base the other day, where they showed me how to build snow caves," he says.
'More and more dangerous'
"They trained me up to try and survive the Rockies. There's no homes up there and the conditions are going to be even worse.
"I'm absolutely fearing the Rocky Mountains. Everyone keeps telling me it can snow a metre deep in a few hours. It's an absolute suicide mission.
"Every day that goes by now the Rockies get more and more dangerous."
As a child Mr McDonald suffered from a debilitating immune deficiency and a rare spinal condition called syringomyelia which meant he struggled to move his legs, and forced him to spend a lot of time in hospital until the age of nine.
"I've continued to move my body ever since and now I'm trying to put it to good use," he said.
The charity run is an attempt to repay his gratitude for the care he received as a child, and is raising money for sick children, including Great Ormond Street Hospital and Gloucestershire's Pied Piper Appeal.
Last year Mr McDonald cycled 14,000 miles from Bangkok to Gloucester in another charity challenge, and last December he set a world record for the longest marathon static cycle ride.