Warminster postman Tom Stokes, who had a heart attack in 2005, is preparing for the biggest challenge of his life in May, when he competes in the UK’s toughest triathlon.

The Rat Race City to the Summit event involves a 2.4-mile swim in the Firth of Forth in Edinburgh, a 112-mile bike ride to Glencoe and a marathon-distance run, which takes competitors to the top of Britain’s highest mountain, Ben Nevis.

Mr Stokes, who lives in Beech Avenue with his wife Verna, took up running on the advice of doctors after his heart attack, competing in his first half-marathon just seven months later.

The 54-year-old has taken part in several more events since, before deciding to change to triathlons in 2011, competing in shorter sprint triathlons and half ironman triathlons. He is a member of Trowbridge’s Hot Chilli Triathlon Club.

He said: “I started running following my heart attack and I was quickly bitten by the running bug.

“I have been training for the City to the Summit event since December to allow for any setbacks, but so far it has been going well. I’ve been trying to build up each aspect slowly, especially progressing the bike distance.

“When I started I was more competitive and focused on getting the best time, but over the last few years I have just concentrated on finishing. The cut-off for finishing is 18 hours, so I’m aiming to do it in about 16 hours.

“It’s going to be tough, especially the run up Ben Nevis, but the most important thing will be nutrition, as I will be burning around 10,000 calories.”

Mr Stokes has previously raised funds for a number of charities. He will be tackling the ironman event in aid of Wiltshire Air Ambulance.

To donate, visit www.justgiving.com/tomthepostie-citytosummit