Higgins is adamant New Zealand boxer Parker deserves at least 40 per cent of a fight against Joshua, the IBF and WBA champion, and won't back down from that. Hearn obviously isn't close to that with his offer.
"I got this weird email from Eddie's email address, but he must have been hacked," Higgins told Sky Sports. "He made the most ridiculously low offer. It could have been the most insulting offer in boxing history.
"He's got my number if he wants to actually make a respectable offer.
"Joseph has earned the right. He's going to put it all on the line and deserves a fair payday. The terms they offered disrespect every kid in the world who wants to become heavyweight world champion and set their family up for life."
Higgins said Parker laughed when he relayed Hearn's offer to him.
Hearn is also negotiating with WBC champion Deontay Wilder for a unification fight, believing that is the bigger bout. Higgins says he's happy to let that progress and Parker, the WBO champion, can come into the unification frame after that.
"We will come to England and fight AJ, but 40 per cent is the bottom line and I can give my word now, not one per cent less," Higgins told Sky Sports.
"They pay us 40 per cent and not a cent less, or they will fight Wilder, who will obviously win and then we'll fight Wilder 50-50. If they want to go fight Wilder, they can, and then we'll fight Wilder on a 50-50 basis later in the year, once he has all three belts."
Parker has viable options to keep him busy with Australian Lucas Browne ready to rumble in March in a trans-Tasman fight that could be lucrative. Fights in China, the United States and Russia are also on the table.
Parker doesn't have to make a mandatory defence until the end of next year so is eager to fight a couple of voluntary bouts if the unification talks stumble as they appear to be doing.
Photo: PHOTOSPORT. Caption: Joseph Parker and his promoter David Higgins are adamant the WBO belt is worth a decent chunk of any purse from a unification fight with Anthony Joshua.