John Fury called out his brother Peter for being a 'cockroach' after his estranged brother joined Anthony Joshua's camp ahead of the Briton's showdown with his son Tyson in December. 

The long-awaited Battle of Britain is set to take place in Cardiff after months of back-and-forth between the Fury and Joshua camps, but neither John nor Peter will be in the corner of the Gypsy King, after Joshua announced this week that Fury's uncle had helped with his preparations. 

Eyebrows were raised due to Peter's family ties, but Fury shrugged off suggestions that Joshua would have the inside track claiming that he hadn't spoken to him in years. 

His father John was even more emphatic in discussion with Playbook Boxing, hinting at a betrayal from his brother which meant that he will 'never speak to him as long as (he) lives.'  

'If he was to do that (talk to Joshua) in any way, shape or form, that would make him the lowest form of human being,' John stressed. 'Even thinking about doing it, that makes him the biggest dog, the biggest untrustworthy dog of all time.

'If he's going to start giving phone calls and advice, meeting in secret, giving him secret sessions, he's a f***ing cockroach.

'The only advice he could have wanted is on Tyson, isn't it? There is no smoke without fire.'

As if speaking directly to Peter, he finished: 'Son, give your head a wobble. Don't sell your soul to the devil for a fiver.'

Peter shared on social media that he had spoken to AJ 'two months ago' about 'advice on his skill set', calling the Londoner 'a really nice guy'. 

'After his fight anything he needs from me (would) be a pleasure. He has a great team around him (including) Team Usyk.'

John may have been staunchly defensive of Fury in the context of Peter doing anything to sabotage him in the ring, but relations between father and son remain minimal after having been, in John's words, 'completely destroyed'. 

The duo are at loggerheads over Fury Junior's career, with his father adamant that he should prioritise his health and wellbeing by retiring for good after two failed attempts. 

Peter previously trained Fury between 2011 and 2017, but left the camp amid a schism with father and son.  

The Gypsy King had previously sought to set the record straight on Peter's involvement with his rival on social media, deeming Joshua's comments 'categorically untrue'.  

'Even if Peter Fury hated me, he’s still my family,' he said. 'That would mean he would be a Fredo, scorpion, snake, rat, b****** piece of s*** if he did that.'