It is the afternoon of September 25, 2000, and Jonathan Edwards is making his way to the triple jump final at the Olympic Stadium in Sydney. In his kitbag are some shirts, spikes, towels – and a tin of sardines.

Why the sardines? They have been chosen by Edwards to symbolise the fish that Jesus used in the miracle of the feeding of the 5,000. They are, if you like, the physical manifestation of his faith in God.

As he enters the stadium, he offers a silent prayer: “I place my destiny in Your hands. Do with me as You will.” A few hours later he has captured the gold medal, securing his status as one of Britain’s greatest athletes.

Edwards’s faith was never an optional add-on. It has been fundamental to his identity – something that has permeated every fibre of his being – since his trips to Sunday school in the company of his devout parents; since he went to a Christian youth camp in North Devon and devoted his life to Jesus, tears streaming down his cheeks and his face glowing with divine revelation. Since he decided to risk everything to follow God’s revealed path, moving to Newcastle in 1987 to become a full-time athlete in the belief that his preordained success would enable him to evangelise to an unbelieving world; since he withdrew from the World Championships in Tokyo in 1991 because his event was scheduled for the Sabbath.

By the time Edwards retired from athletics in 2003, he had established himself as one of Britain’s most prominent born-again Christians. He soon landed the job of fronting a landmark documentary on the life of St Paul and also secured the presenting role on the BBC’s flagship religious programme, Songs of Praise. He looked to have made the transition to life after sport with a sureness of touch that eludes so many professional athletes. Perhaps this was another advantage of his bedrock faith in God.

But even as he toured the nation’s churches with his BBC crew, Edwards was confronting an apocalyptic realisation: that it was all a grand mistake; that his epiphany was nothing more than self-delusion; that his inner sense of God’s presence was fictitious; that the decisions he had taken in life were based on a false premise; that the Bible is not literal truth but literal falsehood; that life is not something imbued with meaning from on high but, possibly, a purposeless accident in an unfeeling universe.

Having left his sport as a dyed-in-the-wool evangelical, Edwards is now, to all intents and purposes, an atheist. But why? It is a question that has reverberated around the Christian community since the rumours began to circulate when Edwards resigned from Songs of Praise in February. Edwards a backslider? Impossible.

I am sitting opposite Edwards, 41, in the garden of his large home in Gosforth on the outskirts of Newcastle, but he does not resemble a man whose world has been turned upside down. His boyish face, cropped with sparkling, silver-grey strands, is alert and alive. One gets the impression that he is looking forward to the ordeal of a lengthy interview. Perhaps he regards it as a kind of confessional, an opportunity to bare all and be done.

“I never doubted my belief in God for a single moment until I retired from sport,” he says. “Faith was the reason that I decided to become a professional athlete, in the same way that it was fundamental to every decision I made. It was the foundation of my existence, the thing that made everything else make sense. It was not a sacrifice to refuse to compete on Sundays during my early career because that would imply that athletics was important in and of itself. It was not. It was always a means to an end: glorifying God.

“But when I retired, something happened that took me by complete surprise. I quickly realised that athletics was more important to my identity than I believed possible. I was the best in the world at what I did and suddenly that was not true any more. With one facet of my identity stripped away, I began to question the others and, from there, there was no stopping. The foundations of my world were slowly crumbling.”

Edwards retains the earnest intensity that was his hallmark when he gave talks and sermons at churches up and down the country. He is a serious person who regards life as a serious business, even if he is now unsure of its deeper meaning. But why did someone with such a penetrating intellect leave it so long to question the beliefs upon which he had constructed his life? “It was as if during my 20-plus-year career in athletics, I had been suspended in time,” he says.

“I was so preoccupied with training and competing that I did not have the time or emotional inclination to question my beliefs. Sport is simple, with simple goals and a simple lifestyle. I was quite happy in a world populated by my family and close friends, people who shared my belief system. Leaving that world to get involved with television and other projects gave me the freedom to question everything.”

“Once you start asking yourself questions like, ‘How do I really know there is a God?’ you are already on the path to unbelief,” Edwards says. “During my documentary on St Paul, some experts raised the possibility that his spectacular conversion on the road to Damascus might have been caused by an epileptic fit. It made me realise that I had taken things for granted that were taught to me as a child without subjecting them to any kind of analysis. When you think about it rationally, it does seem incredibly improbable that there is a God.”

Would Edwards have been as successful a sportsman had he been assailed by such doubts? It is a question that the world record-holder confronts with bracing candour. “Looking back now, I can see that my faith was not only pivotal to my decision to take up sport but also my success,” he says. “I was always dismissive of sports psychology when I was competing, but I now realise that my belief in God was sports psychology in all but name.”

Muhammad Ali once asked: “How can I lose when I have Allah on my side?” Edwards understands the potency of such beliefs, even as he questions their philosophical legitimacy.

“Believing in something beyond the self can have a hugely beneficial psychological impact, even if the belief is fallacious,” he says. “It provided a profound sense of reassurance for me because I took the view that the result was in God’s hands. He would love me, win, lose or draw. The tin of sardines I took to the Olympic final in Sydney was a tangible reminder of that.”

The upheaval of recent months has not left Edwards emotionally scarred, at least not visibly. “I am not unhappy about the fact that there might not be a God,” he says. “I don’t feel that my life has a big, gaping hole in it. In some ways I feel more human than I ever have. There is more reality in my existence than when I was full-on as a believer. It is a completely different world to the one I inhabited for 37 years, so there are feelings of unfamiliarity.

“There have also been issues to address in terms of my relationships with family and friends, many of whom are Christians. But I feel internally happier than at any time of my life, more content within my own skin. Maybe it is because I am not viewing the world through a specific set of spectacles.”

“The only inner problem that I face now is a philosophical one,” Edwards says. “If there is no God, does that mean that life has no purpose? Does it mean that personal existence ends at death? They are thoughts that do my head in. One thing that I can say, however, is that even if I am unable to discover some fundamental purpose to life, this will not give me a reason to return to Christianity. Just because something is unpalatable does not mean that it is not true.”

His crisis of faith offers a metaphysical dimension to the inner turmoil that afflicts so many sportsmen on their retirement. Some will say he has journeyed from light into darkness, others that he has journeyed from darkness into light – but none could doubt the honesty with which he has travelled. The Eric Liddell of his generation has sacrificed his religious beliefs on the altar of intellectual honesty, a martyr of a kind.

World of his own

— A committed Christian, Edwards refused to compete on a Sunday until 1993, most notably missing the 1991 World Championships in Tokyo. “It is an outward sign that God comes first in my life,” he said at the time.

— Contested the World Championships for the first time in 1993, the first of five successive appearances, winning a medal at each one, including gold in 1995 and 2001.

— There was little hint of his 12 months to come in 1995 when, the previous year, he finished sixth at the European Championships, second at the Commonwealth Games and was ranked No 9 in the world.

— Edwards’s life changed in 1995, when he set three world and seven British records, achieving the unprecedented feat of two world records in his first two jumps of the final of the World Championships in Gothenburg. His 18.29 metres that day remains the world record. His wind-assisted 18.43, to win the European Cup in Lille, is the longest triple jump on record.

— A run of 22 consecutive victories ended when he finished second to Kenny Harrison, of the United States, at the 1996 Atlanta Olympic Games. Edwards had finished 23rd and 35th in his two previous Olympics and finished second and third at the World Championships between Atlanta and the 2000 Olympics in Sydney, where he took gold.