They are in the gym in Abercorn, preparing for his fight with Sakio Bika. It’s a stinking hot afternoon in September, 2006, and Joe is wishing he was somewhere else. The demons that have afflicted him since boyhood are chipping away at his confidence. He’s gasping for a drink, battling with his weight and his father is chirping away about some complete irrelevance “Did you hear me, Joe?” Enzo asks. “I said ITV have been in touch. They’re talking about a documentary.”

“Yeah, I heard you,” Joe snaps. “What sort of documentary?”

“I don’t know,” his father says. “They just want to come down and film you.”

“Film me? Where? Doing what? What’s it about?”

“Just speak to them Joe.” “No, I’m not interested.” “What do you mean you’re not interested? That’s crazy! How the f*** can you not be interested?”

“Look dad, we’ve had this conversation before; I’ve told you not to bother me with any celebrity bullshit.”

“That’s crazy. You’ve got to think about things like this . . . you’ve got to project yourself more.”

“No dad, I’ve got to keep winning . . . that’s my only priority.”

“I’ve told them to pop down tomorrow.”

“What!” “I said you’d talk to them after training.”

“No, dad, I’m not talking to anyone – you speak to them. You’re the guy who wants to be the pop star.”

“ Vaffanculo!” Enzo explodes.

“Ahh, go away you f****** donkey,” Joe retorts.

This is the story of a strange kind of love.

Before Joe was acknowledged as the greatest British boxer of our time, before Enzo was acclaimed on Sports Personality of the Year, before the fame or the glory or anyone had ever associated la famiglia Calzaghe and Wales, there was a father, a son and a long and desperate road.

The year is 1969. 20-year-old Enzo Calzalghe has just completed national service in Milan and returned to the family home in Bancali, Sardinia. Since the age of 13, he has worked on the island as a butcher, a barman, a chef, a cleaner, a clothes shop assistant and has been a bass guitarist with his uncle’s band. It’s called survival. But now he wants more.

He packs his guitar and a small suitcase and sets off to discover Europe. He spends the next two years sleeping on park benches and busking on streets. “My father was hard as a rock and worked his guts out,” he says. “My mother had four jobs . . . I worked from the age of 12 . . . Nothing in Sardinia came easy but it made you hard inside. It was my choice to travel the world. I chose my own path. I wanted it. I didn’t fear nothing. I woke up with a smile in the morning and money or no money . . . it didn’t bother me one damn bit. I was healthy. I felt sane. I have nothing to eat? No problem. I will find something tomorrow.”

The year is 1971. Enzo wakes up one morning in a small village on the outskirts of Dijon with a very sore head. He has had a few drinks. He has no idea how he got there. He shoves out his thumb and decides to head south but ends up in Le Havre. There’s a boat leaving for Southampton. He meets a guy driving to Wales. They arrive at a Wimpy restaurant in Cardiff and order something to eat.

Enzo takes a shine to the waitress. Her name is Jackie Phillips. She agrees to meet him after work. They are married four weeks later. Enzo returns with his bride to Sardinia. She doesn’t settle. They decide to leave for London. Home is a B&B on St Mark’s Road in Hammersmith. Enzo takes a factory job making nails and screws. Jackie works as a secretary at 20th Century Fox. In March 1972, their first child is born. They call him Joe.

The year is 1984: La famiglia Calzaghe – Enzo, Jackie, Joe, Sonia and Melissa – have made their home near Cardiff, on a small council estate in Pentwynmawr. Jackie is content. Enzo isn’t sure. He works as a bus conductor. He sells windows. He’s playing with his brother in a band. In the valleys they call him “the running man”. There’s an itch he just can’t scratch.

One day, he decides to introduce Joe to the joys of hitchhiking. They set off together from Pentwynmawr and with just a small flick of the thumb, they have crossed the Severn Bridge and arrived in Bristol. A few hours later, they are drinking tea with Uncle Uccio in Milton Keynes.

Joe’s fondest childhood memories are those road trips . . . the orchard near Bristol where they often lunched on cooking apples . . . the joy of a warm haulage truck on a snowy afternoon . . . his father’s ability to engage the driver with chat . . .

“So, where are you heading?” “London. You?” “To my brother’s in Milton Keynes . . . we play together in a band. Have you heard of The Barron Knights?”

“Yeah.” “We supported them last week.” Joe was cut from very different cloth; shy and timid, he had a face like a choirboy (nobody had ever mistaken Enzo for a choirboy) and was bullied at school. He dreamt of a career with Juventus but was never going to be good enough. The bullying left scars and he struggled with exams. He took a job putting stickers on cakes and hated it. But the most extraordinary things happened whenever he laced a boxing glove . . .

The first time he stepped into a ring to spar he was shocked. He caught his opponent flush on the chin and almost knocked him out. “How did that happen?” he wondered. “Did he slip?” At age 13, he won his first Welsh schoolboys’ title and qualified for the national finals at the Assembly Rooms in Derby.

Enzo had been spending a lot of time with his band but just made it to Derby for the final. Joe raced out of the corner, threw a flurry of punches and captured his first national title in 35 seconds. Enzo was ecstatic: “This kid has real talent.” Joe was hooked: “This is what I was born to do.”

Suddenly, the extrovert and his introvert son were singing off the same hymn sheet: they were off to conquer the world. The hardest part of Joe’s new vocation was the starving to make the weight. Enzo understood hard. He had been brought up hard and spent many a hard night starving on park benches. But training and starving was a whole new ball game. Training and starving was cruel. Joe often tired of his demands. The runs on Kendon Hill ...

“Dad, I’m not going running in the snow.”

“Well forget about boxing then. If you don’t train you won't make it.” ... and the workouts in the gym... “I want you to do 50 press-ups, Joe, and 50 sit-ups.”

“F*** off. I’m tired, I’m not doing that.” “What did you just say?” ... and the impact on his social life... “I’m not boxing any more.” “What do you mean?” “I want to do my own thing, Dad. I want to go over to my friend’s house.”

“Well you can’t.” Sometimes, during sparring, the tensions would boil over and he would nail Enzo with a blow. “Come on then!” his father would erupt. “Let’s go outside and we’ll make it a street fight.”

But the storm always passed. The month is August, 1999. Six years have passed since Joe Calzaghe turned professional. Two years have passed since he became world champion. He is undefeated in 27 fights but is struggling with injuries and his career has reached a crossroads. He has sacked Enzo as his trainer. Colin Hart breaks the story in The Sun. “Joe Calzaghe has sacked his father just as he enters the most important phase of his career. Enzo Calzaghe began coaching his son when Joe was nine and he turned the boy into a star. But Frank Warren, Joe’s manager and promoter, has insisted the WBO world super middleweight champion must now make a clean break from his dad.

“Warren said, ‘I have been promoting for nearly 25 years and I’ve had to make some very difficult decisions, but telling Joe and his father the time had come for them to part was perhaps the hardest thing I have had to do. I shall never forget the look of misery on Joe’s face. Joe and Enzo are extremely close and I felt bad at doing this, but sometimes you have to be cruel to be kind. I feel Enzo has taken Joe as far as he can and someone else should take over. And I didn’t pull any punches. I told Joe quite forcibly I think he has become complacent and, where his father is concerned, he is the one calling the shots. Enzo agreed that Joe has been cutting corners in training and that couldn’t go on.”

In the months that followed, Joe mulled over the choice of a new trainer. Enzo had made it easy for him: “Joe, first and foremost you’re my son,” he said, “and that’s what matters. Whatever decision you make will be fine by me.” Joe didn’t believe him. He knew, deep down, his father was devastated and when push came to shove he couldn’t do it.

“Fighters are great at finding excuses and going through six or seven different trainers when the only thing that needs training is their own attitude,” he says. “No one can motivate me or get underneath my skin the way my dad can. He’s my blood.”

Calzaghe was a different fighter in the years that followed. He had become arrogant and had stared to belittle opponents. He decided he was going to change. “I started watching interviews of myself and it was like I was trying to mimic [Chris] Eubank or Naz [Naseem Hamed] mouthing off. It wasn’t me.”

His reign as the undefeated World Super Middleweight Champion continued ... three years ... four years ... five ... England barely noticed. Naseem, Audley Harrison and Amir Khan continued to grab the headlines. Would Calzaghe ever step from the shadows? It would take a career-defining fight against a top-ranked American.

The month is February, 2006. He is sitting on a train bound for Newport from Paddington feeling utter despair. The big fight with Jeff Lacy is two weeks away. He has spent the morning in Harley Street with a damaged left wrist and the prognosis isn’t good: “You won’t be able to punch with the hand for at least a week,” a specialist opines.

He phones his Dad. “The fight’s off.” “What do you mean?” snaps Enzo. They’ve given me a shot of cortisone. I can’t spar for a week. I’ll have to postpone.”

Enzo’s not buying it. “Joe, listen,” he says. “If you don’t want to fight, it’s up to you. Pull out of the fight if that’s what you want, but you have to realise that you’re going to be a laughing stock if you do.”

“What are you talking about? My hand’s not right. You want me to box Jeff Lacy with a bad hand? Fight him one-handed?”

“You will beat the crap out of Jeff Lacy. Believe me because you don’t believe in yourself. It doesn’t matter about your wrist. It doesn’t matter that you haven’t sparred. You’re going to smash this guy. The guy is nothing but you’re going to be a laughing stock if you call off with your wrist injury.”

“What are you saying? I can’t win this fight with one hand.”

“Joe, if you’re not going to fight this fight, you might as well retire. You’ll lose all credibility. Lacy won’t come back. You’ll be damaged goods. They’ll remember you as a f****** chicken. Is that what you want?”

Enzo wins the argument. Joe returns to the gym. Two weeks later he pulverises Lacy with the finest performance of his career.

“I think I was feeling sorry for myself,” Joe says. “I had just had a cortisone injection. I couldn’t move my hand. I was thinking, ‘Bloody hell! Two weeks to go and I haven’t sparred’. But my fitness was spot-on and he said what I needed to hear. He has always been good at that. He knows what makes me tick.”

The month is March, 2008. Training has finished for the night and Enzo and Joe Calzaghe are sitting side by side in the gym. Twenty-six years have passed since Joe first laced a boxing glove. Nineteen years have passed since he tasted defeat. Eleven years have passed since he became world champion. He has never felt more at peace with himself. Or with his Dad.

“I think things have eased off as I’ve got older,” Joe says. “When I was a teenager it was like a cauldron. We were seeing each other every day and Bang!, it would all go off. But 10 minutes later we were fine. It’s easier now. We do our job in the gym and know when to switch off. We will go to the bookies and have a bet. We will make a cup of tea. We love each other. We are the best of friends.”

“What about your character, Joe?” I ask. “Who do you most resemble? Are you a Phillips or a Calzaghe?”

His eyes flicker briefly with uncertainty: “I don’t know, I would say it is a bit of both,” he replies. “I think I have got some of my mum and some of my dad as well ... they are both fiery characters.”

He directs the question to Enzo. “Who would you say I am like? Phillips or Calzaghe?”

Enzo is emphatic. “Calzaghe,” he says. “Maybe I’m a bit more like my mum,” Joe argues.

“Yeah, definitely your mum,” Enzo concurs.

“They’re both nuts,” Joe laughs. “They’re both fruitcakes.”

“What about a cup of tea?” Enzo suggests.

“Yeah, get it on,” Joe says.

No Ordinary Joe: Joe Calzaghe (with Brian Doogan) is published by Century, £18.99.