By Mark Staniforth

Frank Warren has criticised David Haye's camp for their failure to agree a heavyweight unification bout with Wladimir Klitschko.

WBA champion Haye and manager Adam Booth opened negotiations with the Klitschko camp over a fight between the Londoner and current IBF and WBO champion Klitschko after the Ukrainian pulled out of a fight with Dereck Chisora last month due to a stomach injury.

But those talks broke down, with both sides blaming each other for failing to agree a showdown which Haye is desperate to set up before his planned retirement date of October 13.

The breakdown led to the resurrection of the Klitschko-Chisora fight, which will now take place in Mannheim, Germany, on April 30.

Chisora's promoter Warren hit out at Haye and his manager on Thursday, saying Booth and Haye only had themselves to blame for the collapse of the deal.

"The contract between ourselves and Wladimir had a get-out clause in it that said he could fight someone else if he pulled out," Warren said.

"It was no secret that they were talking to Haye but thankfully, true to form, Adam Booth and David Haye made it an easy decision for them.

"I read some of the things that have been said from Adam Booth and David Haye about how difficult the Klitschkos were, but I have dealt with them on two occasions and I can honestly say that Adam Booth is without a doubt the most difficult person I've ever had to deal with in boxing.

"What is he (Haye) doing fighting Audley Harrison when he could have fought Klitschko?

"You have to be an idiot not to know that they (the Klitschkos) want to make the (Haye) fight."

Warren maintains that Haye's loss is his fighter's gain despite Chisora being a huge underdog for the clash given that he only has 14 professional fights to his name.

What Chisora lacks in experience, he certainly makes up for in confidence.

"I can't wait to get into the ring and smash the living daylights out of Wladimir," said Chisora, 27.

"He has so many weaknesses. "I don't care how many fights I've had. I would have taken him on in my first fight."

Wladimir maintains that a fight with Haye is still possible and could happen as soon as July.

That has led many to suggest that 'Dr Steelhammer' is using the Chisora fight as a warm-up for a contest with Haye which would end a long-running feud between the pair.

Warren denies that but admits Chisora's status as a big outsider means a win for the Londoner would be a huge upset.

He said: "For a guy to win a heavyweight title after just 14 fights has to be the biggest upset of all time.

"It would be a bigger upset than (Leon) Spinks beating (Muhammad) Ali because Spinks came in as Olympic champion.

"There are a lot of people out there who think this is a total mis-match but they're wrong," he added.

"He is going to give Klitschko a fight."

British and Commonwealth champion Chisora, who last fought in September, will have a chance to take on WBC champion Vitali Klitschko if he beats his younger sibling this spring.

Chisora wants to unify all four titles to go down as one of the British boxing greats.

"Winning the world title after 14 fights would be amazing," Chisora said.

"My goal is to unify all the titles. "That would mean I'd be bigger than Lennox Lewis and Frank Bruno because I'd have won my first title after 14 fights."

Chisora also has his sights set on a fight with Haye, who he believes would put his retirement back to set up an all-British showdown.

"If he doesn't retire then I could fight him," Chisora said.

"He would postpone retirement to fight me. He hasn't earned much money in the game so yeah, why not?"