Dereck Chisora: From drugs and weapons to a fight with Dr Ironfist

It was an almighty scrap 12 years ago on Cricklewood Broadway, improbably enough, that set Dereck "Del Boy" Chisora on a path that tomorrow night sees him challenge for the heavyweight boxing championship of the world. Cricklewood to Hollywood? Not quite. But Cricklewood to Munich will do for now.

The Olympiahalle München will host Chisora's fight against the WBC champion Vitali Klitschko, and the challenger acknowledges the champ as a "great" opponent. It might be true that the older Klitschko brother has risen in an age of mediocrity, but his nickname of Dr Ironfist is far from fanciful; his career knockout percentage is the highest in heavyweight boxing history.

Almost every pundit thinks that, whether or not he extends his 88.9 per cent knockout record against Chisora, Klitschko – who has 15 world-title fights behind him – will retain his title with relative ease. He hasn't been beaten since fighting Lennox Lewis in June 2003, and when the referee stopped that contest before the seventh round the Ukrainian was ahead on all three scorecards. Chisora, by contrast, will step into the ring tomorrow having suffered two defeats in the last three outings, and although one of them, against the Finn Robert Helenius, in Helsinki in December, was a hugely contentious points decision, his is hardly a record to worry Dr Ironfist.

On the other hand, Klitschko is 40 now, fully 12 years older than the challenger. And yet not even Chisora considers that a weakness. "Yeah, he's an old man, but he's a wise man," he tells me. "But I'm going to win, I'm going to be world champion. Why? Because I think he'll lose focus. No one has ever really pushed him by getting stuck into him from the start. That's what I'll be doing, like a gladiator, and I'll make him lose his focus."

While not even Chisora's greatest fans would liken him to Sonny Liston or Mike Tyson, there is something of the pavement brawler about him that might just discomfort Klitschko. Certainly, the wrong side of the law is familiar territory to him. "I got into some trouble, man," he says, sitting back on a sofa in his German hotel. "Some nonsense, some serious nonsense. Guns, drugs... I was in the wrong place at the wrong time. I did probation for three years." He also, more recently, was handed a suspended 12-week prison sentence for assaulting a former girlfriend.

Which takes us back to Cricklewood, in north-west London, 12 years ago. Chisora had only just arrived in England from his native Zimbabwe. "I was a good street fighter, man," he says, eyes gleaming. "It was my first fight in London. There was a gang of us on bikes, and me and my friends were chucking tomatoes at each other, having fun. But one of my tomatoes hit this guy, who comes over and takes a swing. I thought, 'This is on!' I jumped on him, pumped him a couple of blows, popped his nose, took a couple of his teeth out. Then he went and got his boys. There were five of them outside my house, so I went outside, man, and rocked it out." Chisora laughs uproariously. "Later, I told my probation officer that story. He said, 'You've got to take up boxing'."

He did. "And after two weeks they put me in the ring with this Irish guy called Pat. This guy went wham, bang, and I thought, 'Sod this shit, he didn't tell me he was going to hit me'. So I went to [trainer] Joe Smyth, who showed me how to move, how to jab. But then I turned pro, and fought a guy called Darren Morgan. The first round, bang! And I'm like, 'Shit, this is the pro game'. I looked at his legs, and I thought, 'This guy is not going to go down. His legs will save him.' So I knew I had to box." Chisora prevailed, on points.

In May 2010 he won the British heavyweight title, stopping Danny Williams in the second round. The money he was beginning to make fuelled his unlikely enthusiasm for antique street furniture – "I'm in the process of getting an old phone box, man," he tells me, excitedly – but not for the details of his own sport. "Some people know it all," he says. "Tyson can tell you everything about every fighter. Me, I don't know anything. Don't even know fighters in my own division. Some of the fighters I've boxed, I've forgot their names."

He said much the same thing to Vitali Klitschko when they met across a table recently, on Frank Warren's TV channel BoxNation, which has the rights to tomorrow's fight. It was a convivial enough encounter by boxing standards, but when Chisora said, "I don't follow boxing," the champion raised an eyebrow. "It is your biggest mistake," he said. "My recommendation, from old generation to young generation, study your opponent."

Chisora just smiled. Without the slightest doubt, he has studied Klitschko closely enough to know that he needs to fight inside the huge Ukrainian's vastly superior reach. It was also how he twice planned to attack the younger Klitschko, Wladimir, before both bouts were called off. "I'm going to destroy his body, destroy his body so the head can't think," he said then.

Whatever the threats, it is not Chisora's style to wind up the opposition, David Haye-style. On the contrary, he has been known to kiss opponents in press conferences, which prompted Klitschko to say that he prefers to kiss only women. "I swing both ways, man," replied Chisora, which sparked a brief flurry of excitement in the media that a top boxer might be proclaiming his bisexuality. "I'm straight, man," insists Chisora, when I ask him outright. "But I support my brothers and sisters if that's the direction they want to take."

Vitali Klitschko v Dereck Chisora will be screened exclusively on BoxNation (Sky 456, Virgin 546)