By Peter Ciani

David Haye said today that he remains determined to bow out in his prime - and has challenged Wladimir Klitschko to show the courage of a true world champion to face him in the ring.

Haye, the WBA champion, had been engaged in protracted negotiations with Ukrainian Klitschko, who holds the IBF and WBO titles and is regarded as the world's best heavyweight, to get a undisputed showdown set for the summer of 2011.

However, earlier this week it was announced that Klitschko will first honour his agreement to fight Haye's fellow Londoner Dereck Chisora on April 30 after a stomach injury forced the champion to pull out of their proposed clash last month, which in turns means Haye will now instead take on mandatory challenger Ruslan Chagaev of Uzbekistan.

Haye was left less than impressed by the whole situation, not pulling any punches in his rhetoric, branding Klitschko a "coward."

Whatever may eventually transpire over the course of 2011, Haye maintains he will stick to the pledge to hang up his gloves when he turns 31 in mid-October.

"I am sure there will be a slight void, but you cannot fight forever," Haye said.

"I have seen fighters who try to fight into their twilight years and you end up just getting beat by younger, fresher, hungrier guys.

"Whether the guy is better than you, it is irrelevant - they are younger, fresh and healthy, while you are old and shock-worn.

"Sooner or later you are going to end up coming a cropper.

"That is how boxing has worked throughout the years, so I want to be one of the very few fighters who gets out on top, in their prime."