Britain's former world middleweight and super-middleweight champion Nigel Benn's first fight since 1996 is off because of a shoulder injury.
The 55-year-old announced his return last month against Cameroonian-Australian Sakio Bika, 40.
They were due to meet in Birmingham on 23 November and Benn revealed the bout was intended to give him "closure".
"With a heavy heart I am sad to say I had to make the hard decision today to hang up my boxing gloves," said Benn.
Writing on Instagram, he added: "I'd like to thank you all for supporting me throughout my career but the time is up for me. I thank you all for giving me an unbelievable career."
Benn, standing alongside his son Conor, who is also a boxer, explained how he had two cortisone injections in both of his shoulders before a sparring session.
"I had to call it quits today, I wanted a hard spar, but it just wasn't happening, " said Benn. "My shoulder started playing up and I could not throw a right hand at all.
"Today's the day I hand over the baton to my son Conor, who is going to carry on the name, but with me it comes to an end today."
The British Boxing Board of Control opposed the contest, which was instead sanctioned by the rival British and Irish Boxing Authority (Biba).
Their vice-president Gianluca di Caro told BBC Sport: "My heart goes out to Nigel, as well as all the boxers scheduled to box on the event.
"I applaud Nigel's good sense not to go ahead with the fight when carrying an injury but I now need to focus on the other fighters that were on the card."
Di Caro said he had spoken to fighters on the undercard in an attempt to "save the show, albeit with a different headline fight".
Former IBF welterweight world champion Joshua Clottey is to face WBF European and international champion Tommy Jacobs and it is hoped to make that a title bout.
Benn, whose last fight was a defeat by Irishman Steve Collins in Manchester for the WBO super-middleweight title 23 years ago, passed all of Biba's medical tests.
Bika held the WBC world super-middleweight title as recently as 2014 and last fought in 2017.