'Called us last night': UFC boss Dana White announces Jon Jones' sudden retirement

UFC boss Dana White has announced Jon Jones, widely regarded as the best MMA fighter of all time, has retired from the sport.

White said Jones told the organisation of his decision on Saturday (AEST) amid attempts to book in a date for a heavyweight title unification bout against interim champion Tom Aspinall.

As a result of Jones' retirement, Aspinall has been elevated to champion.

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"Jon Jones called us last night and retired," White told press in Azerbaijan.

"Jon Jones is officially retired. Tom Aspinall is the heavyweight champion of the UFC."

Jones himself has not yet commented on the news. The fight with Aspinall was expected to be one of the biggest in UFC heavyweight history, but a perceived disinterest in the fight from Jones led many to accuse him of ducking Aspinall.

"I obviously feel bad for Tom that he lost all that time and money, but we'll make it up to him," White said.

"Tom Aspinall is a good guy. He's been incredible through this whole process that we've gone through. He's been willing to do anything - fight him anywhere and anytime and do this, and now he's like, 'I'll fight anybody. You tell me who, and I'll fight him.'

"So, Aspinall has been great. He's going to be a great heavyweight champion for us, and I'm excited to work with him."

Shortly after White made the announcement, Aspinall took to social media to respond to the news.

"For you fans, it's time to get this heavyweight division going," he wrote.

"An active undisputed champion."