Conor Benn was summoned to a hearing on 21 October, before which he "relinquished" his boxing licence amid a failed drugs test just days before his highly anticipated bout with Chris Eubank Jr (33).
Amid confusion and controversy, the fight wasn't called off until just a few days prior to the early October all-British affair after it transpired Benn had failed a VADA drugs test - although he has maintained his innocence since then.
Trace amounts of the fertility drug clomiphene, which elevates testosterone levels in men, had shown up in a test taken by the Voluntary Anti-Doping Association (VADA).
A BBBofC statement said: "On the morning of the hearing, Mr Benn voluntarily relinquished his licence with the BBBofC.
"In accordance with its rules and regulations, the board determined the allegations following the hearing at which Mr Benn was legally represented.
"The allegations of misconduct against Mr Benn were upheld."
Earlier on Wednesday Benn's promoter, Eddie Hearn, claimed the British slugger has a big fight on his hands to get his career back on track.
"It's a little bit difficult for us because Conor Benn has an ongoing legal situation and we can't say too much around the process, because it's prejudiced to his case," Hearn said while appearing on talkSPORT.
"Conor Benn is straight away presumed guilty without any kind of hearing, because that's generally the way it works in this situation."
Despite failing the VADA drugs test, Benn did pass all tests with UKAD, who are also recognised by the BBBofC.
Late on Wednesday evening Benn appeared to release a statement on his social media accounts in which he "strongly refutes the allegations of misconduct."
Written in the third person, Benn claimed that "Conor's focus at this time is solely on clearing his name."
"The board, however, has made it extremely difficult for Conor to focus on doing that by its conduct of an unfair and biased procedure.
"In such circumstances, Conor decided not to renew his licence (which had lapsed). Conor told the Board that if it did not accept that his licence had lapsed, then he renounces it.
"He strongly refutes the allegation of misconduct (which for the avoidance of doubt is *not* in relation to the VADA issue) and firmly believes that an independent tribunal will reach a wholly different conclusion.
"At an appropriate time Conor will speak out on this and on the doping allegation, to the extent that he can whilst legal proceedings are ongoing. In the meantime he reiterates, in no uncertain terms, that he is a clean athlete."