Herbie Hide caused a ringside riot in Bethnal Green on Sunday, after Audley Harrison racked up the 11th win of his career.
Hide stood on a chair to taunt Harrison and his supporters after the Olympic champion's second round win over Mathew Ellis.
Hide pushed a female ringside fan to the floor, causing a stampede around one side of the ring which had spectators scurrying for cover.
Moments earlier, Harrison had grabbed the ring microphone to ask his supporters whether he ought to next meet Hide or Frank Bruno, who was also at ringside.
As the familiar "Bruno" restrains echoed around the venue, Hide instead received boos.
The police were called to the scene and are now investigating the incident.
A Scotland Yard spokesman said: "We were called at 23.09 on the 31 (May)
to York Hall to reports of a woman being assaulted inside the venue.
"On arrival, police spoke to the woman. She declined medical attention at the
scene. There have been no arrests and inquiries are continuing."
The row marred a good test for Harrison, who struggled at first before overcoming Ellis after one minute 35 seconds of round two.
Harrison had been given a definite scare by the battling Blackpool man in the opening three minutes before finishing him off in explosive fashion.
A superb left uppercut sent Ellis toppling to the canvas for the first time and although he twice clambered to his feet Harrison produced a clinical finish.
It was predictable and I'm very, very cross about it
Ellis crashed again to a left hook and when he was bundled over for the third time referee Terry O'Connor wisely waved the contest off.
Simon Block, general secretary of British Boxing Board of Control, said: "I said before the show it was not a good idea to have two boxers in such close proximity.
"It was predictable - everything was fine after the contest and the trouble started here at ringside and I'm very, very cross about it.
"I don't know who's to blame but certainly the security wasn't adequate and
bringing two fighters together in that situation wasn't advisable.
"Boxers are supposed to be disciplined and tonight at least one of them wasn't. I shall be looking at the video tape to see exactly what happened."