You need a big heart to contemplate a six-day slog across the Sahara, running through 145 miles of sand in temperatures touching 120F with a 25lb pack on your back. You need an anti-venom pump and distress flares too (both regulation requirements) and, as Hilton-Barber points out with Saharan dryness, "corpse repatriation insurance". "It means that if you die in the desert, they guarantee to ship your bones back home," he said. "Very reassuring."
In the case of Hilton-Barber, you also need the reassurance of a guide. When he sets off from Ouarzazate in southern Morocco next Sunday, he will be running every step of the way clutching an eight-foot tape attached to Jon Cook, a fellow resident of Duffield in Derbyshire. Blindness has not deterred this inestimable soul from the challenge of the world's toughest race.
"It's funny," he said, a mug of tea in one hand and Ivor, his guide dog, at his feet, "but I keep thinking about an interview I overheard when I was waiting to talk on a programme at Pebble Mill last year. This chap was talking about an experiment with a pike in a tank of water. It was put in with a whole lot of minnows but with a sheet of glass in between and the pike spent two weeks trying to eat them, bruising its nose all the time, before realising it couldn't and stopped. They then slid the glass out and the pike made no attempt to eat the little fish. It had been conditioned to think that it couldn't.
"It struck me, while I was listening, that it's a lot like that for people with disabilities. You're told you're not expected to do this or that. And I think we've got to challenge a lot of these perceptions. One of my major goals in doing this race is to encourage all people with disabilities to look at their circumstances as a challenge rather than a handicap, whatever their problems are. That's a big thing for me."
It is a big thing for his big brother too. Like Miles, two years his junior at 50, Geoff Hilton-Barber has been blind since his teenage years. Both suffer from retinitis pigmentosa, a genetic hereditary eye disease. Geoff, who lives in Durban, will also be running in the Marathon des Sables, guided by his wife, Carol. The Hilton-Barbers will be breaking new ground, as the first blind runners to compete in the marathon of sand, as its title translates. It will not, though, be the first time Geoff has broken beyond the perceived barriers of his disability. Last year he sailed from Durban to Fremantle in 51 days, aided by nothing more than speech output on his navigation equipment.
It was the first solo ocean crossing by a blind person and, clearly, an inspiration to his brother. "I work as an employment consultant for the Royal National Institute for the Blind," Miles said, "and I often say to people, `If my brother can cross the Southern Ocean blind, then maybe you can cross a street on your own using a long cane.' I'm not saying that other people should try to sail across an ocean solo or run across a desert. But I am saying, `Think again about limitations that you've readily accepted. They may not be valid limitations and they may be depriving you of a quality of life and an independence that you think you've lost.' You don't have to have 20:20 vision to have quality of life and to be happy.
"Of course my attitude was different when I lost my sight. Lost my confidence, too. I didn't want to use a guide dog because I thought I would be accepting defeat, losing control over my life. But Ivor has actually given me back my independence. I don't consider my blindness to be a disability. It doesn't disable me. It just forces me to use different ways of doing things.
"I think we've all got some sort of disability, even able-bodied people, in the sense that we limit ourselves. We're not aware of our true potential. Before I started training for the London Marathon last year I couldn't run 50 yards without being totally out of breath and having to stop, bend down, and catch my breath. Now I'm going to run 145 miles through a desert with a pack on my back."
He will do so leaving a bemused family (wife Stephanie, daughters Deborah, 20, and Abigail, 19, and son, David, 15) back in Duffield. "They all think I'm mad," Miles said, "but their attitude is, `So what's new?' I've done over 40 parachute jumps and gone white-water rafting down the Zambezi." He has also managed to shoehorn some hard labouring preparation into an already crowded weekly schedule in the last eight months, running 26 miles on Saturday mornings and testing his endurance with a 43-mile effort on trails through the Peak District three weeks ago. He has even run a marathon through the sand dunes of Norfolk with Cook, his intrepid guide.
"It's very hard going," Hilton-Barber conceded. "If you imagine running up and down steep hills blindfolded you get an idea. You don't know what your foot's going to go on to. Every step is a step into the unknown. In the dunes marathon I fell about six times. I also lost my sense of balance. With the speed of going up and down, I lost all idea of where the vertical was. I was dizzy, as if I was drunk. I had to stop and let my middle ear stabilise.
"It's a lot of responsibility for Jonathan. I have an eight- foot lead attached to his pack and he's continually shouting instructions at me about the terrain and I've got to try to adjust all the time, as to where to put my feet. I've just got to put one foot wrong in the desert and I can break an ankle. That could be our limiting factor - if we suffer a physical break - because I don't think we'll be broken mentally. We know it's going to be a painful experience. You just have to cope with the pain and focus on other things."
And Miles will have much to contemplate as he pushes himself through the physical pain and the miles and miles of Saharan sand. He will be thinking of the RNIB's development of a standard CD player for talking books, for which his efforts will be raising much-needed funds. He will also be thinking of the 14-year-old blind girl who was inspired to extend the boundaries of her own physical endeavours after listening to a television report about him abseiling down a university tower block - and of Chris Moon, who finished 283rd of 355 competitors in the 1997 Marathon des Sables.
"That's what's inspired me," he said. "If a man who had an arm and a leg blown off by a landmine can run the toughest foot race in the world, then why can't I?" It's a question we able-bodied lesser mortals could pose ourselves as the remarkable Hilton-Barbers set off on their desert journey of enlightenment.Reuse content