Oleksandr Usyk is set to walk away from negotiations for the proposed undisputed heavyweight title bout against Tyson Fury, according to a report by BBC Sport.

The two men who between them hold the four major titles in the sport’s heavyweight fold had been set to clash on April 29 at Wembley Stadium in London but the talks have hit a road block understood to be related to an immediate rematch contractual clause insisted upon by Usyk’s team.

Usyk and his representatives had previously agreed to a 70/30 split of revenue in Fury’s favour, with the fight thought just days ago to have been essentially agreed. The undefeated Ukrainian boxer is said to have requested a similar clause that he agreed to in his pair of fights with Anthony Joshua, which afforded the Briton a change to avenge his first loss in a second fight.

Fury’s camp, though, are thought to be against the idea as it could fracture the undisputed heavyweight titles if a rematch was to occur. Usyk presently holds the WBA (Super), IBF, WBO and Ring magazine title belts, while Fury is the WBC heavyweight champion. A rematch clause was initially agreed upon, the BBC says, before talks fell apart over the potential purse on offer in a second fight.

The winner of the hypothetical April 29 clash would have been the heavyweight division’s first undisputed champion since 1999 when Lennox Lewis defeated Evander Holyfield. There has never been an undisputed heavyweight champion at any point in the four-belt era.

It is understood that Usyk will instead pursue a WBA title defence against another English fighter, Daniel Dubois.