I knew there was something seriously wrong with my paraglider when its wing appeared beneath me. One moment my craft was flying normally, the next its wing had turned inside out and was flailing around beneath my feet.
I reacted in an instant and went through the emergency routine for dealing with collapsed wings. With a giant whoosh, the canopy reinflated and swung me violently upwards like a giant yo-yo. I'd fallen about 80ft and just missed the ground. A moment later the canopy shuddered and collapsed again, sending me into freefall for about 30ft and tumbling head over heels on to a rocky hillside.
The world stopped moving, and I was cocooned inside soft, warm cotton wool. Everything was dark but I could sense a bright light. I wasn't frightened or in pain. I was completely at peace with myself and the world.
After what seemed an eternity, I forced myself to open my eyes. I felt strangely calm and began methodically inspecting myself for damage. I touched my eyes, moved my jaw to check it wasn't broken, and made sure there was no sticky yellow fluid coming from my ears.
As soon as I checked my right leg, I almost blanked out with the pain. It was the most glorioussensation I've ever felt. If I was in pain, I reasoned, I was alive, but more importantly I hadn't broken my back or neck.
The relief of being in agony didn't last long. I had visions of shards of bone poking through the skin, which as it turned out, wasn't too far from the truth. I tried to calm myself down by meditating and attempted to convince myself that my legs were simply bruised. It worked. Briefly. Then, I quickly slipped into shock and began shaking violently. Each time the seizures gripped my body, the ends of the broken bones ground against each other and sent waves of excruciating pain up and down my leg.
When I arrived at hospital in Gloucester, the doctors discovered that the lower half of my right leg had been driven through the knee joint into my thigh. The tibial plateau, or lower knee joint, had broken into six pieces and the tibia and fibula had shattered into six main chunks and a few smaller chips. There was also massive damage to the muscles, tendons and cartilage. The specialists told me it was one of the "top five" broken legs they'd seen.
"You've certainly done a good job on it," said the doctor. "You've got exactly the same injuries as Joe Simpson" - he's the mountaineer whose fall into a crevasse and subsequent escape in the Andes was chronicled in the book and film Touching the Void.
There was, I was told, a 75 per cent chance of serious complications, ranging from "wound breakdown" - where the leg turns to mush and begins to rot - through to amputation. If I recovered, it was unlikely I'd ever be able to walk without pain. Arthritis was a certainty.
It took a few moments for the words to sink into my morphine-drenched brain. Amputation? Hmmm. Quite serious then.
There was a glimmer of hope, though - a new surgical procedure that offered the possibility of reconstructing my leg and knee joint.
I was transferred to a specialist unit at the Bristol Royal Infirmary, where I was to have a Taylor Spatial Frame fitted. This device, whose use in the UK was pioneered by surgeons in Bristol, looks like a medieval torture implement.
It consists of four aluminium rings that encircled my lower leg. Fourteen metal spokes and two bolts connected these rings to the shards of bone inside my leg. The spokes and rings of the frame can all move independently and allowed the surgeons to move bone fragments around inside my leg.
In essence, the Taylor Spatial Frame replaces traditional hospital "traction" and the plates and screws currently used to fix severely broken bones. As a result, bones can be rebuilt or even progressively "stretched" to lengthen limbs pulverised and shortened in accidents.
I was very lucky to have one of the frames fitted, as they are extremely costly and require a huge support team of surgeons, specialist nurses and physiotherapists. They are barely one step beyond the experimental, and as a result only a few hundred are fitted in the UK each year. This will change as the frames are much more effective at treating badly broken legs. Each sets the NHS back about £25,000, which is still a lot cheaper than amputating a leg, which costs the state about £300,000.
Life with the frame was very difficult. I could barely sleep and the pain was only controlled with powerful drugs, leaving me washed-out and jaded. I had to cope with using a wheelchair. It was a completely different world, one in which you are often treated as an utterly dispensable second-class citizen.
This was rammed home to me when I tried to use a zebra crossing near my home. Nobody would stop for me, even though I was clearly in a wheelchair. After several minutes of anxious waiting one car did stop, but by the time I reached the middle of the crossing, cars (mostly SUVs, it has to be said) began driving around me. To them, I was just another obstacle on the school run.
I was petrified, embarrassed and angry in equal measure. It was my first day out after weeks in hospital and everyone regarded me as a nuisance, a non-person, a waste of space.
After that, I realised that I could be beaten by my accident or I could fight back and make a full recovery. Mark Jackson, the surgeon, and the physiotherapists all repeatedly told me that recovery was down to me. They had done their best to put me back together. My mind was going to be crucial. I could force myself to recover by force of will or I could be passive and make a less than perfect recovery.
Forcing yourself to be positive is far easier said than done and I spent a fair amount of time feeling sorry for myself and annoying my girlfriend, Bella. I managed to keep my spirits up by constantly telling myself that I would make a 100 per cent recovery. I refused to allow any negative thoughts into my head.
Each evening, I would think of five good things that had happened to me that day. I'd then drift off to sleep visualising myself running across open plains and climbing mountains. I imagined a powerful blueish-white light sweeping up and down my leg, healing as it moved. I visualised the cartilage cells of my knee dividing, regenerating and repairing the damaged joint. I also prayed each night, and probably meant it for the first time in my life.
I improved my diet, too. I eliminated all dairy products from my already vegetarian diet because I believe they leach calcium from bones. I cut back on bread and made up for it with pulses such as lentils. I ate masses of spinach, cabbage, broccoli and oranges - all known to help bone growth. I took a daily multivitamin, a calcium supplement, and glucosamine (with chondroitin) tablets, which are believed to aid joint health.
I spent about 22 hours a week doing physiotherapy. At first it was agonising. Hardly a day passed without me collapsing in tears. The hospital physiotherapists forced my knee to bend even though I was screaming with pain. It was the best thing they could do for me, but at the time it felt like torture. Now, I can only thank them repeatedly for all the effort they put in.
I gradually regained use of my knee and the pain subsided to virtually nothing. After three months, I was allowed to start walking without crutches. It was one of the most important days of my life. I clearly remember gingerly touching the floor with my toe and wondering whether my leg would collapse under the weight. It didn't - and amazingly I felt no pain whatsoever.
Six weeks later, I had the frame removed. I was lucky; some people have the frames on for two or three years. Now, a year after the frame was removed, I can walk 15 miles and have just started running (albeit like a 90-year-old). I've also started gliding lessons, but I'm unsure whether I'll take up the sport. Every time I think of flying, I can hear the words of a venerable Independent on Sunday editor ringing in my ears. "In my experience," said Peter Wilby, "no one ever got hurt sitting in a nice chair, by the fire, with a good glass of brandy." I think he may be on to something.
The Taylor Spatial Frame
* The Russian physician Gavril Abramovich Ilizarov developed the first prototypes of the frame at the end of the Second World War and in the early 1950s to help soldiers recover from severe fractures and bone deformities.
* The first Ilizarov frames were made from bicycle wheels and spokes. They were ignored by the West until 1981, when Italian surgeons began using them.
* In the late 1990s, the American surgeon Russell Taylor modified the Ilizarov frame so that bone fragments could be independently and progressively moved inside the limb. This allows surgeons to position fragments of bone very precisely to aid healing, and to move them again with no need for a second operation.
* Adjustments are calculated by computer and carried out by the patient. They are made by twisting a series of dials on the frame, which then moves the fragments of bone around inside the limb.
* Several hundred Taylor Spatial Frames are fitted in the UK each year. This is set to increase as they become the standard treatment for severely broken limbs.