Derek Chisora is already inside the Daily Mail offices when Deontay Wilder arrives.

Forty minutes early – an anomaly for a fighter notorious for running on his own clock – Chisora is dressed all in black, understated, a beanie pulled low. He looks relaxed, but the calm feels deceptive. April 4 is coming, and Chisora knows exactly what that date could mean.

Wilder’s arrival shifts the atmosphere instantly. The former WBC heavyweight champion strides through the building wearing his long brown ‘Bronze Bomber’ jacket, a diamond chain hanging from his neck, catching the office lights as heads lift from keyboards across the newsroom. A few reporters subtly swivel in their chairs. Others pretend not to stare. Everyone clocks him.

Before heading to the studio, the two heavyweights take a tour of the offices together, stopping at the sports desk – ‘where all the action happens,’ as Chisora puts it. Wilder grins and jokes that he’s keeping people employed with the things he says, especially when it comes to Tyson Fury. He doesn’t unleash his trademark ‘BOMB SQUAD’ roar, much to the quiet relief of those nearby – though he laughs afterwards and admits he probably should have.

This head-to-head interview, staged ahead of their April 4 clash at London’s O2 Arena, was designed to preview a heavyweight shoot-out. Instead, it became something far more revealing: Chisora opening up on therapy and the terror of retirement, Wilder detailing how promoters took his money while he lay injured in a hospital bed, and both men laying bare why they believe boxing remains a brutal, ‘scummy’ business and why that reality will shape what happens when they finally collide.

Despite security protocol placing them in separate greenscreen rooms, with guards keeping a careful watch, there is no hostility when they come face to face. They hug. They chat. They catch up properly. Chisora even offers Wilder access to one of his three boxing gyms for fight week in April after Wilder admits he is still looking for somewhere to train.

There is, however, one flash of tension. Grinning mischievously, Chisora accuses Wilder of a sex tape that has recently surfaced. Wilder immediately denies it, shaking his head and insisting it isn’t true, brushing the claim aside. Chisora laughs, smirking, and keeps teasing him about it throughout the day – playful rather than poisonous, a reminder that even friends can throw a few jabs outside of the ring.

Deontay Wilder and Derek Chisora visited Daily Mail HQ in London for a head-to-head interview

Despite security protocol placing them in separate green screen rooms, with guards keeping a careful watch, there was no hostility when they come face to face to begin with

They catch up properly. Chisora even offers Wilder access to one of his three boxing gyms for fight week in April after Wilder admits he is still looking for somewhere to train

For now though, there is warmth. The violence can wait.

When the conversation begins, it is Chisora who goes first and not with bravado, but vulnerability.

‘I see a therapist about retirement,’ he says. ‘And when I talk about it, it’s scary. Retirement is very scary. ‘You have to understand, from amateurs your life is already mapped out.

‘You go to school, come back, get your bag, go to the gym, come back, do your homework, go to bed. Then you turn pro and it’s the same thing, just on a bigger scale. People tell you what to eat, what to do, what to be. That’s your whole life.

‘And then one day you get a knock. ‘It’s retirement. You need to retire tomorrow.’ And that’s it. The door shuts. You don’t know anything else.’

Money, he explains, does nothing to fill the void.

‘Yes, you’ve got money, but money doesn’t make you happy. What made you happy was the suffering – the running, the sparring, being in the boxing gym. That’s where your purpose was.’

The fear, he says, is losing his identity.

‘That’s the scary part. Very, very scary and not just for me, for everybody,’ Chisora says. ‘That’s why a lot of athletes, when they retire, they don’t have anything else. So what do they do? They pick up a bottle and start drinking. They’re trying to run away from something they can’t run away from.’

When the chat begins, it is Chisora who goes first and not with bravado, but vulnerability

Wilder pictured during his photoshoot at the Daily Mail office in London on Tuesday

The emotions surfaced before his last fight in Manchester, when he believed it could be the final walk of his career.

‘I cried walking to the ring,’ he admits. ‘I was crying. It’s very emotional. It’s scary. You don’t know if that’s the last time.’

Yet when asked if he is content with what he has achieved, Chisora smiles.

‘I was hated, then I was loved,’ he says. ‘You can’t beat that. At the beginning of my career, everybody hated me, even my friends. They were saying, ‘That’s not boxing.’ I was just doing what I needed to do to make money. Then suddenly they liked it. Became fans.

‘But it’s hard, because you wake up on a Monday and you’re like, ‘Wow, I’m retired. What’s next?’ School run.’

Wilder listens closely. When he speaks, he is less emotional and more angry.

For him, boxing stopped being a sport long ago.

‘This is a business,’ Wilder says. ‘People call it a sport, but when you’re in it, you understand it’s a business. When you don’t know the business, it’s fun. You’re happy. Winning is exciting. But when you start seeing certain things for yourself, it changes everything.’

Wilder and Chisora sat down with Daily Mail Sport’s Charlotte Daly to discuss their fight

The pair also met with Daily Mail’s Head of Sport Chris Dean in the office on Tuesday

He describes moments when life outside the ring crept in at the worst possible time.

‘You’ve got people calling you days before the fight. You’re arguing with loved ones. Regular people don’t understand what we go through as fighters, they never will. They don’t understand what it means to risk your life and your money at the same time.’

Then he goes further, describing being betrayed he suffered while laying in a hospital injured after one of his fights.

‘When something happens and you’re hurt, they don’t even want to pay the hospital bill,’ Wilder says. ‘You’re barely getting by. They did it to Shannon Briggs – left him in Germany and took all his money. And they did it to me too.

‘I was fighting on a Don King card. I broke my hand, my arm, I’ve been through all kinds of situations. Promoters put up million-dollar insurance, but they don’t expect to spend it. They just want the show to go on. ‘Whatever it takes to put this show on.’ And when the warriors get in there, may God be with them – I just want that money.’

He pauses, then delivers the line that sums up his worldview.

‘There are some people who genuinely care about fighters. Very few. But most of the industry? It’s criminals and whores. That’s what it is. I speak the truth about it.’

Chisora nods and distils it into something simpler.

‘It’s a scumbag sport,’ he says. ‘Scumbag moves behind the scenes. But guess what? We’re scumbags too, because we’re in a scumbag game. If you’re not, you get eaten.’

It is why Wilder believes knockouts are the only justice left – a belief forged by what he insists happened in his trilogy with Fury. Wilder says those fights stripped him of any remaining trust in judges, officials and the system itself, convincing him that unless an opponent is rendered unconscious, nothing is guaranteed.

‘You can’t leave it in the judges’ hands,’ he says. ‘When you knock somebody out, that’s the ultimate answer. Nothing can happen from that point. You know the result.’

That mentality will define April 4.

The fight almost happened in December. It didn’t because Chisora walked away from a deal he felt was unfair.

‘When they sent me the contract, it wasn’t good,’ he says. ‘And when something good is meant to happen, an angel comes.’

That angel, he says, was MF Pro.

‘They gave me the best contract I’ve had in 20 years,’ Chisora says. ‘I showed it to my father. He said, ‘Who gave you this?’ Everything was fair. Everything was 50-50. That’s beautiful.’

Wilder agrees. Talks with Oleksandr Usyk fizzled. The focus returned to Chisora.

‘We’re of age now,’ Wilder says. ‘I’m not going to sit around and wait for Usyk. I needed to get back into the ring and get a fight under my belt.’

Daily Mail Sport exclusively revealed that the bout will take place at London’s iconic O2 Arena, not the venue originally proposed

The fight on April 4 will be co-promoted by MF Pro and Queensberry Promotions

After the interview, the tension fades again. The fighters hug once more. Chisora repeats his offer of gym access for fight week. Then he makes another suggestion, a luxury sauna in Victoria. £100 per person. Caviar if they want it.

Wilder smiles. He’s in.

So they leave the Daily Mail offices together – reporters watching them disappear down the street – still friends for now, knowing that on April 4 the hugs will stop, the honesty will hurt, and only one of them will walk away with the ending he’s been trying not to face.