John Shackleton has a track record for endurance walking, clocking up 51 miles in a day three years ago when he raised a bumper £7,500 for the charity Cancer Research UK, for which he has raised another £1,000 since.

Back then his target was 51 miles, one for each year of his age, and he followed the Mary Towneley Loop bridleway route. Now, at 54, he is facing what he describes as his ultimate challenge - 100 miles in the Yoredale 100, an event organised by the Long Distance Walking Association.

It's the walk of John's dreams, both in terms of walking country and the mental and physical challenge it represents, and once again he will be walking to raise money for Cancer Research UK.

John, of Higher Eastwood, Todmorden, explained that the Long Distance Walking Association host the 100-mile two-day challenge in a different part of the country each year and he made certain of getting his entry in for the event held in the Dales.

"I have known it was coming to Skipton for three years and I have loved the Dales since I was a kid. We always had one day a year when mum and dad would take us up to the Dales and I have always had an affinity with it," he said.

"So to spend two days walking through it...if the weather's good it could be blissful," he said.

John, an experienced distance walker, is aware that mental toughness and physical fitness will be paramount, but he is relishing the challenge.

"I've been renovating a house for the last 18 months - I've been stuck inside and I'm an outdoor person. It's limited my walking, so it's been great to get out onto the hills again," he said.

Working on a limited timescale John suffered a bad injury setback in January when he pulled a calf muscle while playing badminton to build up anaerobic strength in his legs.

He is now playing catch up but since taking to the hills again he has experienced no reaction to the injury and with six weeks to go until the May 24 and 25 walk is working up the miles in conditions which have varied from superbly sunny one week to last Sunday's blizzard.

Happy with nature and walking comfortably and well, John didn't mind either, although cool and dry on the days of the walk itself would be welcomed!

Equally important, he says, is the mental effort needed to sustain walkers on an endurance challenge like this where, due to physical fatigue and lack of sleep, many start to lose their lucidity by the end, although rigorous safety systems are in place.

He has spoken to Todmorden distance walker Steve Perry, who covered some vast distances while on his own marathons, including conquering all 284 Scottish Munros in winter, and Steve has been pleased to give John some additional tips.

Age should not, he believes be a problem, as the average age of walkers tackling the challenge each year is around 53, many having stayed with it since the 100-miler started in 1973.