Anthony Joshua is relishing fighting for the IBF heavyweight title at Tyson Fury’s expense.

Joshua is to challenge Daniel Dubois, who was elevated to the status of champion when Oleksandr Usyk vacated his title, at Wembley Stadium on September 21.

The development means that the reign of the first undisputed heavyweight champion for a quarter of a century has ended before that champion even had a chance to make a solitary defence of his title. It also means that Fury, scheduled to fight Usyk in a rematch – this time for the WBA, WBO and WBC titles – on December 21 may never realise his dream of being the undisputed heavyweight champion of the world.

Joshua, 34, first won the IBF title when stopping Charles Martin in 2016, before Dubois had even made his professional debut. If Joshua believes that fighting for the title heightens the significance of their fight he regardless resisted saying so. Instead he is satisfied that his long-term rival and potential future opponent – if Joshua defeats Dubois in September he will remain on course to challenge the winner of Usyk-Fury II – will be frustrated by what is to come.

"I'm glad Fury isn't the undisputed champion,” he said. “I just think he's an idiot.

“If it was someone else I might think it was a shame [that there’s no longer an undisputed champion]. I've always said he's an idiot; he's very disrespectful. Not in a way I care, but I just feel like he thinks by stepping on other people that makes him feel better

“I'm not in competition with no one. I'm in my own lane but he has to step on people to make himself feel good and that's not good.

“The way he disrespected Usyk – rabbit this and middleweight that – it’s not good for the sport. If I respect you and you respect me we can lift this sport up and people think we are two of the most elite fighters in the world.

“But Fury will step on you and make you look like a guy who's just walked out of a pub and he's not on your level. Then he goes and gets spanked [by Usyk] – he deserves it.

“It's up to him what he says. Usyk is a good fighter – there is no denying it – just give him his flowers and move on.”

In Joshua’s past fight he stopped in two rounds Francis Ngannou, who Fury had previously struggled to a narrow points victory over. It was that that led to Joshua’s installation as the next opponent for the winner of the two fights between Fury and Usyk – a status he risks if he loses to Dubois, 26.

“In a way [I want Fury to beat Usyk],” Joshua continued. “I don't mind anymore whether he wins or loses. I just want to fight him – it's been dragging on. Fury ducks a lot of people – he doesn't fight many people. Many top-tier people. He needs to get on with it and come and fight me and stop wasting my time. I don't want to wait until I'm 40; 41; 42 to fight him.

“It's up to him [if he wants to retire if he loses to Usyk again]. He's put himself in a position to make his own decisions. In terms of the fans – I know what they want. We tried to make the fight happen, it was signed and then it fell apart. We had the [Deontay] Wilder fight signed... I've always stepped up. Hopefully after this we can get it on, finally.

“I fought Ngannou to show Fury the level we're on. ‘Fury fought him? I'll fight him.’ I tried to fight opponents Fury has boxed against [Otto Wallin was another] to showcase that we're here and on the same level.”