The walk will take Chris Moon more than three weeks

Chris Moon, 41, of Basingstoke, Hants, hopes to raise �1m for charity by walking 52 miles - the same as two marathons - every day for three weeks.

The father-of-two left John O'Groats at 0415 BST on Saturday to begin the 1,284 miles to Land's End, where he hopes to finish on 29 June.

He said: "I am keen to show that we can all achieve our goals.

"I'm taking on the One Walk challenge for Leonard Cheshire because no-one goes further to support disabled people."

The charity is the largest voluntary sector provider of support to 21,000 disabled people around the country.

He was the first leg amputee to run the 250km Great Sahara Run

Mr Moon was injured when he worked for a landmine clearance company in 1995.

The Sandhurst graduate, who later served with several infantry units, had been walking in what he thought was a mine-cleared area in Mozambique when the mine exploded.

He ran the London Marathon within a year of leaving hospital and in 1997 became the first leg amputee to run what is described as the toughest foot race on earth - the 250km Great Sahara Run.

He has also climbed Mount Kilimanjaro in Tanzania and completed the 100km Kumamoto volcano run in Japan.

During his marathon walk, members of RAF Kinloss and Lossiemouth will take turns to walk with Mr Moon.