Serving prisoner Steve Gallant took on knifeman Usman Khan with a narwhal tusk and a chair at the Learning Together rehabilitation project event, in Fishmongers’ Hall, London, on November 29. Jack Merritt and Saskia Jones died in the attack.
Gallant, one of two men convicted of killing Barrie Jackson in Hull in 2005, had been allowed out on licence that day for the first time since his sentencing.
The 42-year-old, who was jailed for a minimum of 17 years, helped restrain Khan on London Bridge before the terrorist was shot dead by police.
Speaking publicly for the first time about Khan’s rampage, Gallant said he heard noises downstairs and went to investigate despite “orders to stay in the conference hall”.
In a statement issued through his lawyers, Hudgells Solicitors, he said: “I could tell something was wrong and had to help. I saw injured people.
“Khan was stood in the foyer with two large knives in his hands.
“He was a clear danger to all, so I didn’t hesitate.”
Using a chair and narwhal tusk handed to him by civil servant Darryn Frost, Gallant tried to hold Khan back.
He said: “Khan also showed us the bomb around his waist in an attempt to frighten us. We then chased him onto London Bridge and restrained him until the police arrived.”
Mr Frost then confronted Khan on the bridge with another narwhal tusk after the first one smashed.
Gallant and James Gilligan were jailed for carrying out a revenge attack on 31-year-old ex-fireman Mr Jackson.
The pair lay in wait for Mr Jackson near the Dolphin pub, on the city’s Longhill estate, after believing he attacked Gallant’s girlfriend.
In 2005 Hull Crown Court heard that the pathologist who examined his body found multiple blunt impact injuries.
Those to his face had shattered the bones underneath, consistent with his being stamped on.
Other injuries were consistent with his being kicked on the ground and a hammer could have been used to cause one or other of his head injuries, the court was told.
Gallant maintained his innocence, claiming that although he took part in an initial attack he withdrew when he thought the victim had “had enough”.
However in 2008 a Court of Appeal judgment dismissed his application to quash the conviction.
Since going to prison, Gallant, who will be eligible for parole in 2022 subject to approval, has “vowed never to turn to violence again”.
Instead he learnt to read and write and is now in his third year of a business studies degree.
He has co-written several plays, one of which was recently performed at the Royal Court Theatre in London, and took part in the Learning Together project, where he worked with a team of students in Cambridge producing legal advice guides and has become a mentor.
Losing Learning Together course co-ordinators Mr Merritt, who he had met in 2016, and Miss Jones was an “unbearable blow” and the “sense of loss is immense”, he said.