Brighton runner Ryan Gayler is preparing for the ultimate sporting challenge - the toughest marathon in the world.

He is in training for the Jungfrau marathon in Switzerland, a run designed to test highly-trained endurance athletes to the limit.

By taking part, he hopes to raise money in memory of baby Harry Downes, who died aged one day last year.

In between training on The Downs, Ryan 36, of Whittingehame Gardens, Brighton, is seeking sponsors to help raise cash for two hospitals.

Now in its tenth year, the Alpine marathon, held in September, has a spectacular setting among three mountains - the Eiger, the Monch and the Jungfrau.

While covering the 26.2 miles, Ryan will climb a mile and a half. Half the course is on roads, the remainder on hiking trails and mountain paths.

He said: "I'm doing as many miles a week as possible, up as many hills as possible, but there is not much I can do to recreate the conditions in Switzerland.

"I'm running 35 to 40 miles a week but I can't get that high above sea level."

Ryan, sign manager at Dockerills ironmongers in Brighton, has run three London marathons, with a best time of three hours 30 minutes. But he is not setting himself a time challenge for the Swiss event.

He said: "They allow you six and a half hours and I would like to do it within five. If I do any better, I will be pleased with myself.

"There are 7,000 people taking part but not many Britons. If I get a chance to look, the scenery is supposed to be breathtaking."

Ryan signed up for the marathon after Harry, the son of his friend and former work colleague Dave Downes, died of heart complications in October.

Harry's parents were so impressed by the skill and dedication of staff at the Trevor Mann Baby Unit at the Royal Sussex County Hospital, Brighton, and Guys Hospital in London, they set up a fund to raise money to buy life-saving equipment.

Anyone wanting to sponsor Ryan can contact him on 01273 607434 or make a donation via Harry's web site at www.babyharry.org.uk