Tom Craig, from Partick, has won a much-coveted spot among the world's fittest people at the Ironman World Championship in Kona, Hawaii, in October.
Tom, 46, secured his spot in the world's toughest endurance race after entering a competition organised by the disability charity Scope, the official charity partner of Ironman UK.
The once-in-a-lifetime opportunity was awarded to Tom, a supporter of the charity, after he made a strong application, where his pledge to raise an incredible £50,000 to support Scope's work with disabled people and their families stood out to judges.
Competition for places at the event is fierce.
Each year 80,000 athletes compete for a slot at Kona, but only 1900 make it to the starting line on race day.
Tom now has just eight months to attain peak fitness and raise his target from sponsors before he stands at the starting line alongside the world's fittest people, facing the prospect of a 2.4-mile rough-water swim, 112-mile bike race and a 26.2-mile marathon.
He will have to complete all of the challenges on the same day, and within 17 hours to qualify as a finisher.
Tom said: "This will be a huge challenge for me. It's like a Sunday league football player being given a shot to play in the World Cup Final."
Tom has previous experience of competing in Ironman races.
Seven years ago, alongside three friends, he completed Ironman Austria, and between them they raised £55,000 for Great Ormond Street Hospital.
Tom said: "When I started training for the Austria event people openly mocked me, because at that point I was severely overweight.
"But I did it, and when we handed over the money to the hospital, it was one of the proudest moments of my life."
But in recent years, Tom's fitness regime has slipped drastically and he says that he now stands at "the foothills of Everest" as he prepares to get back in shape.
Glasgow-born Tom currently splits his time between his family in Hertfordshire and the Middle East where he consults on telecommunications issues.