A British man is attempting to run the fastest lap of Iceland to raise money for a children’s cancer charity.

Seb Key, 25, from Dorset, aims to run the 1,265km (786 miles) road that circles Iceland and beat the previous record of 27 days.

He has completed 10 days so far, running for over eight hours a day in temperatures often falling below freezing while he aims to raise £50,000 for the charity Children With Cancer.

Mr Key told the PA news agency the amount he has run “feels mad” but there’s “still a long way” to go.

He said: “So far, it’s been the most surreal feeling because it’s every day taking my body to the point of not being able to walk or run.”

The day normally ends when he simply “sits down” and says he can’t run any further.

Pushing his body to the limit on Iceland has already earned him a laundry list of injuries.

He came into the challenge with Achilles tendinitis from his training and quickly developing “jabbing pains” in his knee.

At the end of day two he collapsed because one of his upper thigh muscles were so inflamed but his worst injury so far is the tenosynovitis in his feet which mean he can’t “pick up his foot on its own”.

His team has figured out it could use elastic bands tied from the front of his laces to his shin to create an “artificial tendon” to pick up the front of his foot.

Despite his injuries, 10 days into the challenge Mr Key’s team say he has found a “rhythm” and is on track to finish the challenge.

Mr Key, who also works for Children With Cancer, has been inspired by his younger sister Libby’s story, as she was diagnosed with a non-cancerous brain tumour the “size of a plum” at just 11 weeks old.

Libby had two invasive surgeries to remove and treat the tumour on her optic nerve and the charity Children With Cancer provided support for Libby and her family after they received the diagnosis.

Mr Key said: “These families, no matter how rubbish their days were before and how exhausted they are, they’re still showing up.

“Some of these children are showing up and still managing to be upbeat about it, and that is the most unreal thing.

“There have been so many mornings already where everyone’s exhausted, but we just think let’s just show up, let’s give it a go, and as long as we’re trying our absolute hardest then we are doing right by them.”

Amar Naher, chief executive of Children With Cancer UK, said: “Seb’s incredible commitment to this challenge will not only help us raise essential funds but also highlight the critical need for ongoing support in childhood cancer research and care.

“His dedication will help us get closer to a world where every child and young adult survives their cancer diagnosis.

“His efforts will have a profound and lasting impact on the families we support.”

Although right now he is focused on the current challenge and he is going to need some “serious time off” afterwards, Mr Key said that there will be more endurance challenges in the future.

“We’ll find something,” he said.

Seb Key’s fundraiser for Children With Cancer can be found at givestar.io/gs/yessebkey.