Audley Harrison remains convinced he will be crowned world champion and insists he will continue his pursuit of redemption with an explosive defeat of Martin Rogan.

Audley Harrison remains convinced he will be crowned world champion and insists he will continue his pursuit of redemption with an explosive defeat of Martin Rogan.

Two days after James DeGale turned professional, his most recent predecessor as a British Olympic gold medallist defended himself against his army of critics.

Since striking gold at Sydney 2000, Harrison has alienated fans with his over-cautious style and bravado.

But a poor record of three defeats in 26 fights has failed to douse the 37-year-old's self-confidence outside the ring and yesterday he outlined his ambition to win a world title.

Reading a bizarre 200-word mission statement from his mobile phone, Harrison branded his critics "donkeys" and vowed "negativity will not deter me from climbing Everest" as he searched for "redemption".

Defeat by rugged Rogan would surely end his career, but the southpaw Londoner has pledged to produce something special at London ExCeL tomorrow night.

"I wanted to be a world champion by 2004 or 2005 but didn't achieve that. When it happens, it will happen, but it is going to happen," he said. "As it didn't happen when I said it would, people want to hang me with it.

"I've seen the light, I will be heavyweight champion of the world. No doubt, 100%.

"I've made adjustments and got back on the horse. Every fight I have is last chance saloon. But I look in the mirror and see far more positives than negatives.

"I was booed after beating George Arias on points in September and everyone said it was a terrible fight. It wasn't a terrible fight, at all.

"Against Rogan I'm going to let off all my guns. When that happens I won't be beaten."

Rogan, a relative newcomer to boxing who, at 37, has a flawless record of 10 victories, was unimpressed by Harrison's performance at the press conference.

"Harrison won his Olympic gold eight years ago, this is now. He's got a great future in preaching and a great future in climbing mountains," he said. "He seems to be preaching a lot and he's been doing that for too long. He should go out and do what he's been talking about."

Enzo Maccarinelli's challenge for the vacant WBO world cruiserweight title tops the bill, although little-known opponent Francisco Alvarez, of Puerto Rico, was only confirmed yesterday morning.

Johnathon Banks, his original adversary, withdrew with an ankle injury and his replacement, Herbie Hide, became unreachable last night after initially agreeing to the fight.

"I heard I was fighting Alvarez only yesterday. I was happy when I heard it was Herbie Hide because he's the only man I really can't stand in boxing," said Maccarinelli.

"He's been saying a lot of things about me, so it would have been nice to shut his mouth up. But he didn't want it."

Amir Khan launches his comeback against Irishman Oisin Fagan on the undercard with the duo duelling for the vacant WBA international lightweight title.

Olympic silver medallist Khan is seeking to rebuild his reputation after being demolished by Breidis Prescott, a little-known Colombian fighter, in 54 seconds in September.

"I've got to prove people wrong about my chin. All fighters have to come back from defeat at some point," said Khan.

"I can handle this fight. I've come back a better fighter, mentally and physically."