Jack Denness will today begin his 15th attempt at the Badwater 135 ultra-marathon, dubbed the most dangerous race in the world.

Mr Denness, from Canon Close, Rochester, will step onto the start line later this evening as he attempts to become the first 80-year-old to complete the 135 mile course, which takes runners through the hostile terrain of Death Valley, California.

Climbing steadily out from Badwater, he will pass through the desert and three mountain ranges, climbing 13,000 feet and descending 8,300 feet over the next 48 hours towards the finish at Mount Whitney, California.

Jack - who is raising money for the Wisdom Hospice - has admitted he is worried about the race, and he’s not the only one.

“This latest one is quite frightening, especially for an 80-year-old man to put himself through this,” said Martyn Reeves, chief executive of the Friends of the Wisdom Hospice. “He’s an amazing man.”

Mr Reeves said he had told Jack in no uncertain terms to put himself, and not the challenge, first.

“He’s lost a lot of weight. I said to him ‘don’t finish it, do what you can. Just signing up for it is amazing, the finishing isn’t important. Stay safe and enjoy it if you can’.”

Mr Reeves said Jack’s support was more than simply financial.

“You can’t add it up, because for example if he goes to do a talk in Gillingham and they donate money, it goes on their database.

“He’s been a stalwart of fund-raising since our inception.

“He’ll do anything for us; he’s a caretaker at school and anything he thinks can be of benefit to us he’ll run up to us. He’s given us old chairs. When we needed some stocks for our summer fair, he went and found some.”

And he added: “It’s all very well having these youngsters undertaking challenges, but when an 80-year-old flies to Las Vegas at his own expense to try to break a record for the oldest runner, more than my hat comes off to him.

“We wish him the best of luck – stay safe and the best of luck.”