MIKE TYSON incredibly knocked out grown men when he was just 12, his former trainer has revealed.

But it was hardly surprising given the future heavyweight champion of the world weighed 13st 5lbs at that age with a neck that was close to 20 inches.

Iron Mike, who even now at 53 still has amazing speed and power, was born to fight, according to respected Teddy Atlas.

In an interview with RingTV.com, Atlas recalled the first time Tyson – who went on to win 50 of his 56 fights with 44 coming by way of KO – came into the gym.

And he said nothing could have prepared him for such a ferocious mix of natural ability and power.

He said: “As far as most pure, God-given talent, raw, from the earliest stage that you saw, it would have to be a 12-year-old Tyson, who was 190lbs but no fat.”

Atlas was one of the legendary Cus D’Amato’s pupils and he said Tyson – who plans to set up a cannabis farm on a Caribbean island – had to impress them both when he took to the ring.

He did.

Atlas – who was famously accused of holding a gun to the head of a teenage Tyson – said: “He had to impress me and Cus. He had to box his first day with a 27-year-old man who was a professional fighter, and he was able to do that.

“You can’t put him in with kids to spar because there are none.

“So you’re hiring sparring partners and they’re men and he’s hurting them and knocking them out.

“Anyone who could be knocking out men when he’s 12, 13 years old is a pretty damn good puncher.

“He learned the technique to make you miss and catch you clean but power’s power and punchers are born not made.”

But what ended the Baddest Man on the Planet’s career was his “will” cracking before his body.

Atlas added: “What wasn’t strong was his will. That’s what cracked.

“His will cracked before his chin. He absorbed those punches and he took big punches before he got knocked out.

“He showed a chin to handle those punches at a very high level.

“His will wasn’t nearly as strong as his chin.”