The two reasons why Dean Macey turned down his invitation to the BBC Sports Personality of the Year programme on Sunday get to the heart of his extraordinary tale.

One: he was due to celebrate his 31st birthday the night before and, now that he is retired, he knew that he would be giving it his all. Indeed, the bin full of empties tells the story, plus the fact that he was entertaining his guests by executing 30-odd press-ups with hand-claps at 3am. As he said of the BBC show: “I didn’t want to be spending most of my time in a urinal, chucking my guts up.”

Two: “I didn’t want to go and get the sympathy vote. I didn’t want to be walking around with people going: ‘Sorry about this, sorry about that.’ Because I’ve never won a world or Olympic gold, I’ve always struggled to accept compliments. I always felt I could have done slightly better.”

So, with his birthday celebrations, as in his entire career as a professional decathlete, Macey was all or nothing. The result, as he acknowledges, was that when he slipped quietly into retirement in July, finally accepting that his body was beaten, he left the sport with questions, not answers. He was a talented, phenomenally driven and compelling athlete, but was his one of the great unfulfilled careers? He finished fourth in two Olympics, won one World Championships silver medal, one bronze and a Commonwealth gold, but how many more medals did he forfeit because he could not control “the beast”?

We are in his sitting room in his home in Canvey Island, Essex, discussing “the beast”, and Macey makes it clear that he is entirely at ease with the deal that he made with it. He also calls “the beast” his “self-destruct chip” – his refusal in training to do anything other than push his body to its limits.

“There’s a time and a place to unleash the beast,” he said, “and I struggled to identify when that time was. The passion took over all the time. There are times in training when you do have to go for it. But you can’t be 100 per cent all the time for nine months. I unleashed the beast every day. Towards the end of my career, on the days when I agreed to train easy, I had physios, doctors, parents ringing me up to remind me.”

More on vomiting: “I loved chucking my guts up. I don’t like the feeling, no, but I loved knowing that I’ve pushed myself to the point where my body doesn’t want to go any farther and thinking: ‘Right, I’m better than where I was an hour ago.’ I loved pushing myself to the point where I was thinking: ‘Probably no one else in the world could do this.’ ” At his best, Macey knows that he was a match for the leading decathletes of his generation – Roman Sebrle, the Czech, and Bryan Clay, of the United States. His attitude to training, however, inflicted on him such an injury toll that he will never know if that was a match he would have won. The only leading decathlon he finished completely fit was when he won his silver medal in 1999.

Thereafter they were all heroic battles; his Commonwealth gold came only three weeks after a grade-two hamstring tear. “I liken it to having a winning lottery ticket but then someone saying: ‘Yes, you’ve won the lottery, but you can’t cash that,’ ” he said. “I felt I had the talent to accomplish anything, but I always pushed myself that bit too far.

“In the ten years I was pro, if I’d trained at 85 per cent, I may have remained uninjured and definitely come in the top six of every major championship, and I’d have picked up medals because there were some weak ones here and there. But I’d have had no chance of a gold. And I wasn’t prepared to do that. That’s why I got hurt, because I wouldn’t settle for second best.”

This approach did not always produce the breezy, bubbly, jack-the-lad of his public persona. He missed the 2002 Commonwealth Games in Manchester, for instance, “the biggest disappointment of my entire career bar none”, when he unleashed the beast in training and snapped a hamstring. “It took probably the whole of that summer to get the disappointment out of my system,” he said. “It was massive. I don’t know how close it was to costing me my marriage, but I know that I was a real f***** to live with for a long time. My wife, Lisa, being there every day and training with me most of the time, takes the brunt of it. She is such a good girl to put up with me. Lots of women would have walked out.

“People always assumed I was great at dealing with things but I wasn’t. I’d come home and smash dishes and pull doors off. Lisa was brilliant. She would let me blow my top and then say: ‘Right, you finished? Let’s go down to Homebase and sort this all out.’ ” The end for Macey was not how he imagined it. “I’d always seen myself in Beijing,” he said, “standing on the line for the 1,500 metres [the last discipline in the decathlon], knowing this was the last 1,500 metres I’d ever run and smashing it, just taking myself to the point where I would tear my guts open. Whatever it took, I’d go out on a high.”

Instead, his last attempt to hit the Olympic qualifying standard show-cased a final, heartbreaking battle. He had already missed three months’ winter training with a slipped disc, but in Hexham, Northumberland, in July he tore one side of his groin in the long jump, the other in the pole vault and, 14 pain-killing injections later, realised that he simply could not move to throw the javelin.

Still, he completed the event. “I was embarrassed,” he said. “I thought: ‘I am a hard, proud man, how can I be reduced to this?’ In the 1,500 I could barely walk to the line.”

How does a proud man deal with retirement? “I struggled for three months,” he said. “I’d walk around and just start filling up. I’d wake up lost. I didn’t know what to do. My emotions were so intense I felt I’d lost a member of the family. I’d lost a major part of my life, something was dead. Everything I’d lived for was over.

“And my mum and Lisa were in tears a lot. They wanted me to give it another go next year, but the reason I retired was I didn’t believe any more I could stay healthy. Once my belief went, I didn’t see light at the end of the tunnel.”

There will be no comeback. To make the point, Macey sold his poles and javelins. The shots and discuses are waiting to go. Instead, he has myriad corporate and media opportunities to explore. What he really enjoys is fishing and there are some television and print opportunities here, too. But where he really sees his future is as a personal trainer, maybe with his own gym, and in athletics, at any level. “I think I’ve got a lot to offer,” he said. “I could be saying to kids: ‘Listen to what I say because I may help you avoid a major disaster.’ ” If only, one concludes, he had been able to heed his own advice. But Macey would disagree. And he certainly would not court sympathy. “I regret getting hurt, but I don’t regret why I got hurt,” he said, almost as an epitaph to his career. “I got hurt because I tried hard.”

Signing off in 2008

Darren Anderton (football). Aged 36, in his 569th club appearance, signed off this month with the only goal in Bournemouth’s win against Chester City.

David Coulthard (Formula One). Aged 37. Won 13 grands prix. Final race was at Interlagos – he spun off after being hit on the first lap.

Lawrence Dallaglio (rugby union). Quit England duty with the 2007 World Cup final as his last game. Retired altogether, aged 35, after leading Wasps to victory in the Guinness Premiership final against Leicester at Twickenham.

Graeme Hick (cricket). Aged 42, retired with more than 40,000 first-class runs. Injury deprived him of a farewell innings.

Mick Fitzgerald (racing). Announced his retirement, aged 38, four months after suffering serious neck injuries in a fall in the Grand National.

Darren Gough (cricket). Aged 38, lasted magnificently for a fast bowler, though his body, not his spirit, eventually gave way.

Richard Hill (rugby union). Another 2003 World Cup-winner, finally called time, aged 34, after fighting two anterior cruciate ligament knee ruptures.

Words by Owen Slot