It will probably surprise readers when William Fox-Pitt says, at the start of his autobiography: ‘I never expected or dreamed of a career as a top event rider.’ Yet he has been a dominant presence in eventing for 13 years, and lists winning Badminton and representing Britain for six unbroken years as some of his many achievements. But why should he choose to release an autobiography now, with no immediate plans to retire? ‘I thought I’d miss the moment,’ he says simply. Aged 38, he is conscious that he is coming to the end of his competitive life, but he is still on winning form: he won seven three-day events this year, including Burghley, but he wasn’t selected for the European Championships team.

‘I’d like to ride Tamarillo (pictured) in the Beijing Olympics next year, and there’s London in 2012. After that, I’ll probably hang up my boots.’Tall (6ft 6in), blonde, handsome, patrician, William nonetheless has a gentle manner that seems at odds with his vital statistics and the swashbuckling feats he performs on a horse. Sitting in the Fox-Pitts’ pretty farmhouse, he strokes Spud the cat and admits to dreading life when the competing finishes. But he is equally aware of the sacrifices he has made along the way. ‘I’ve got a lovely wife and two children, and I’m not prepared to go on missing days and weekends forever.’ He loves eventing because ‘for someone who loves horses and riding, it’s the ultimate thrill’. But he is candid about the flip side: ‘You get injured, and it puts things in perspective. You lose a horse, and you realise how tough it is. You lose a friend, and you think, what are we doing?’ A friend from William’s Pony Club days, Polly Phillipps, died after a fall in 1999: a black year in which eventing suffered five fatalities.

He confesses to visiting Badminton as a teenager and thinking, ‘Don’t be funny. I’m never going to ride around here.’ His mother, who rode around Badminton several times herself, must have thought differently. Marietta Fox-Pitt is the first in a series of strong female figures who feature in the autobiography, and William gives her full credit for kick-starting his career. ‘My mother gave me the chance to find out if I was any good. She calls me for advice now.’ When did that start? ‘Oh, only recently!’ His first girlfriend and first wife, Wiggy Channer, stepped into the breach when he left home at 24, organising her life to accommodate his career. Wiggy’s affair with eventer Andrew Nicholson brought an end to the four-year marriage, and in the book, these moments get a frank treatment: William describes the ‘torment’ he felt and the ‘moments of vacillation’ when he wondered if he and Wiggy should stay together. ‘I wasn’t prepared to write this book unless it was open.’

His alliance with Alice Plunkett, the action-girl who rode around Badminton and Aintree and who is now a racing commentator for Channel 4, heralded happier times. They married in 2003, and have two sons, Oliver and Thomas. ‘We call eventing jumping jumps. It keeps things in perspective.’He mentions perspective a lot, and one gets the impression that it’s something that he’s battled with: on the one hand giving eventing his all, on the other realising that it is inherently frustrating and dangerous. When it comes to problems in the eventing world at large, he is conscious that he is often a lonely voice of dissent. At Badminton this year, 25% of the riders withdrew their horses because the going was considered too hard. Many complained that such a prestigious event could fall foul of dry weather, but it was William who called for a new course designer. ‘I’m not frightened of speaking out, even if it makes me unpopular, as it can help in the long term.’

He is certain that he will stay involved when he retires from competition. William and Alice both want to train racehorses one day. There is a sign in their kitchen saying, ‘Better to die of overwork than to die of boredom’. I am sure that William will be at the centre of the horse world for years to come.

‘What Will Be: The Autobiography’ (£20) is published by Orion