You may be wondering why a boxing website is writing about a UFC heavyweight champion's contract.

The answer lies in the increasingly public battle between Eddie Hearn and Dana White. Ever since White announced his move into boxing through the Saudi-backed Zuffa Boxing venture, the pair have traded jabs from opposite sides of combat sports. White landed an early blow by luring away Conor Benn, one of Matchroom's biggest stars.

Then Hearn found himself inside White's world, acting as an adviser to UFC heavyweight champion Tom Aspinall. At first it seemed Hearn's role was to build Aspinall’s commercial value outside of the octagon and would have no involvement within it.

Now that seems to have changed and, according to Hearn, Aspinall is not happy.

“I was always advising him across his UFC position and contract,” Hearn said. “Tom Aspinall is the boss. So we will give him our advice and he will decide what he wants to do. He won't mind me saying he's not happy, but he also understands at the same point he’s signed a contract. So we can't sit here and cry too much, but you just hope that people are fair.”

In Hearn's eyes, Aspinall's current deal does not reflect the revenue he generates for the UFC.

“When you're getting one-fiftieth of the revenue of a show to main event for the UFC heavyweight world championship, how can anybody possibly suggest that it's fair?” Hearn said. “And it's not a normal situation for Tom Aspinall.

“He's had four eye operations coming off that fight [against Ciryl Gane in October]. And now you want to see him get back in the ring for… Honestly, by the time he's paid his expenses and paid his tax, in my opinion – this is not Tom's opinion necessarily – my opinion is, what's the fucking point?

“Like, do you really want to risk your health for nothing?” Hearn continued. “I mean, nothing. You're not even going to make anywhere near seven figures by the time you're finished. Yet there's $50 million of revenue in the show. It's absolutely obscene.”

Hearn again stressed that these are his opinions and not necessarily that of Aspinall’s, but his client must soon make a decision about his future in the UFC.

“I've got a call with Tom to go through everything this week, because he will have to make a decision at some point,” he said. “And listen, maybe those guys want to freeze him out and try and be clever, or maybe they want to be honourable and say, look, Tom Aspinall against Alex Pereira is a massive fight. Massive fight. So are we going to be fair? This is what we suggest. Maybe there's an extension to the contract.”

Many believe that Hearn plans on maneuvering a move to break Aspinall out of his deal with the UFC and into boxing where he fought once, nine years ago, stopping the 12-2–1 Tamas Bajzath in one round.

“That's not true at all,” Hearn said. “Tom's very happy to remain in the UFC, but he also feels as heavyweight world champion and with the revenue that's in the pot, that just a little bit of respect would be nice.”

Hearn believes that Aspinall is currently being neglected in more ways than one.

“It's just a weird set-up where he doesn't get invited to UFC London. They text him an hour before the start saying, ‘Do you want to come tonight?’ He lives four hours away,” Hearn explained. “I mean, how can he not be ringside at the White House for [Alex] Pereira against [Ciryl] Gane [on June 15]? He's fighting the winner.

“Can you imagine me having the heavyweight world champion, and there's a fight for the interim championship where the winner has to fight him and this guy's not even invited. I mean, it's mental. But this is the arrogance of it all. So my job is to act in the best interest of Tom Aspinall.”

There have been fighters disgruntled by their pay in the UFC for years, but White’s move into professional boxing with Zuffa – where he is reportedly paying boxers considerably more than their counterparts in the octagon – has resparked the argument.

“How can you have a situation where a fighter is making 15 times more than [Aspinall], yet there's a fifth of the revenue in the fight? It just doesn't make sense,” said Hearn. “I knew this was going to happen, where it's really going to kick them in the face this whole boxing thing, because they're paying the boxers so much more than the UFC guys, yet the UFC business is making $800m a year.

“I think it's unfair. But it just would never happen in boxing because the advisors and the managers are that much more advanced, where they know what's in the pot. And in the pot, we pay 80 per cent to the fighters, roughly.”

Despite Hearn’s criticism, he yet again affirmed that he’s “not looking to breach Aspinall's contract and terminate it”. However, he did have an ultimatum for the UFC.

Hearn challenged the organization to pay Aspinall what he is deserved, or release him so that he can work alongside Most Valuable Promotions in making Aspinall versus Francis Ngannou on their new MMA platform.

“Tom would love to fight Francis Ngannou, but it's very unlikely that the UFC would do anything honorable and potentially release Tom Aspinall from his contract,” Hearn said. “You've got enough money to pay him properly, but you just wouldn't do it because you're so arrogant.

“But if you don't really want to do it and you don't really like Tom Aspinall, which clearly they're giving him no support, no brand value, no profile building, then let him go. If you don't see the value in him, let him go. And, of course, in that situation, and this is why they'd never let him go, we would do Francis Ngannou against Tom Aspinall, and it would be absolutely huge.

“And Tom Aspinall would make 10 times more than he's making in his current contract.”

Whether Hearn's criticisms carry any weight inside the UFC remains to be seen. But his battle with Dana White is no longer confined to boxing.