Frank Warren is planning to take legal action against the British Boxing Board of Control over their stance concerning the planned heavyweight bout between David Haye and Dereck Chisora.
Former two-weight world champion Haye has signed up to face Chisora on July 14 at Upton Park - a grudge match which is taking place under a licence from Luxembourg as neither fighter holds a British licence.
Undercard boxers on the controversial bill will have their licences revoked, according to the BBBofC.
The domestic sport's governing body said last month that all those involved in the show - including promoters, managers, fighters and seconds - would instantly have their licences stripped without a hearing.
The Board adjusted its stance on Friday, saying that any participant would be called to a hearing under regulation 4.9 of the BBBofC rules and regulations, which states: "A licence-holder's licence may be suspended or withdrawn by the Board: if, having called the licence-holder before it, it reasonably considers that it is not in the interests or the welfare of boxing that the licence-holder should continue to hold his licence."
Warren called that "an embarrassing climb-down".
He added in a statement - "I still take the Board's threat to call me to account for my role in the fight as Dereck Chisora's manager as unlawful. The Board seems to have pre-judged the issue without hearing the point of view of any of its members and this is just wrong. I intend to issue proceedings next week and will support all other licence-holders who feel intimidated into not participating in the Haye v Chisora promotion.
"I may not be the only one suing the Board. The Board has also stopped fighters such as Kevin Mitchell, who I also manage, from fighting on the undercard. This is such a shame as Kevin was looking forward to fighting in front of the crowd at West Ham and it would have been great for the fans to see him again. He is asking the Board to reconsider and it may be forced to do so rather than face proceedings from Kevin for the purse he would have earned together with the lost opportunity to fight in front of 40,000 people."