Lennox Lewis has suggested he may retire from the sport after ruling out a heavyweight clash with Vladimir Klitschko.

The Ukrainian boxer, the current WBO champion, had been hailed by many as the likeliest successor to Lewis.

But on Monday, the WBC, IBF and IBO heavyweight champion scuppered any chances of a bout.

Lewis said: "Vladimir Klitschko - he's not tough enough.

"He's not ready for me yet. It would be a waste of my time to go and fight him - I would knock him out.

"I've already done everything that I really wanted to do in the sport of boxing, so I'm going to keep them guessing for a little while longer."

Lewis was speaking at Michael Watson's testimonial in London, a month after defending his heavyweight crown against Mike Tyson.

Keeping them guessing

The Briton halted the threat of the American in blistering fashion, causing the fight to be stopped in the eighth round in Memphis.

Following his victory, there were calls for the 36-year-old to retire from the sport having achieved the pinnacle of his career.

But he refused to be drawn on making a final decision.