Former heavyweight world champion Mike Tyson has claimed that he fought while high on cocaine and even used a fake penis to trick drug testers.

The 47-year-old makes the sensational claims in his new autobiography 'The Undisputed Truth' where he describes in detail how he first tried cocaine when he was just 11 years old and even used the substance before one of his fights.

"The history of war is the history of drugs. Every great general and warrior from the beginning of time was high," writes Tyson before explaining how he became a "full-blown cokehead".

Tyson claims that he spent much of his career addicted to cocaine and marijuana, admitting that he took drugs before his shock loss to Londoner Danny Williams back in July 2004 in Louisville.

Four years earlier he had tested positive for marijuana after defeating Andrew Golota and subsequently had his boxing licence suspended. He donated $200,000 to various charities and was back in the ring less than a year later.

But it seems that was not Tyson's only indiscretion in 2000 as he admits to using a fake penis to avoid failing a drugs test before his bout with Lou Savarese at Hampden Park in June 2000.

The native New Yorker says he took "blow" and "pot" before the fight and then filled his "whizzer" - what he uses to describe his fake penis - with someone else's urine.

Tyson even suggests that the reason he did eventually fail a drugs test was because the member of his entourage whose job it was to carry the "whizzer" failed to hand it over to him.

The former unified heavyweight champion also goes on to reveal how he took cocaine before his now-notorious press conference with Lennox Lewis back in January 2002.

Tyson unleashed a tirade of abuse on the Brit and even managed to bite him on the leg as security tried to break the pair up.

"I lost my mind," writes Tyson. "I looked over at him and wanted to hit the mother****r."

Tyson, who still holds the record as the youngest boxer to win the WBC, WBA and IBF heavyweight titles, has been through years of rehab for his various addictions

"I'm a bad guy. I did a lot of bad things and I want to be forgiven. I want to change my life. I want to live my life sober," said Tyson. "I don't want to die. I'm on the verge of dying because I'm a vicious alcoholic."

Despite his troubles since retiring from boxing back in 2005, Tyson has enjoyed success away from the sport appearing in hit film The Hangover and going on to star in his own one-man Broadway show.