The agent of Joseph Parker has claimed that Anthony Joshua is "refusing to compromise" on terms for next year's proposed unification clash.
Reigning WBA super and IBF title holder Joshua intends to face both Parker and Deontay Wilder next year if an agreement can be reached.
Duco Sports representative David Higgins outlined last month that Parker is not prepared to take less than 35% of the purse for a high-profile bout with Joshua, however, and talks remain at an impasse heading into the final weeks of 2017.
"We started at what we thought was a fair ratio, and then a concession was given on our side," Higgins told Sky Sports News. "The truth is we were getting pretty close, and then there was talk of me going to London, but I made it clear I won't unless there was a concession on the Joshua side.
"Frankly we thought there would be, but no, it's been signalled there won't be. As far as we're concerned, that's it for now. I won't be boarding a plane until we are closer. As it stands, AJ is refusing to compromise and has drawn a line in the sand that we think is unreasonable. It's not worth me coming to London."
Higgins suggested last week that Barcelona's Camp Nou would be an ideal venue to host the fight, should it get the go-ahead.
