A gay army veteran, who served in Afghanistan and Northern Ireland, stepped in to shutdown a homophobic attack by a belligerent and violently homophobic man on a bus in London.

Former Grenadier Guardsman Lee Wardle, who works as a bartender at a gay bar, said he heard a man having a loud conversation on his phone that was full of bigoted remarks.

The vet told the Evening Standard the man appeared to have been talking about having gone to a gay club with the goal of picking up women.

"He had some sort of altercation with an individual about this," Wardle said. "I think he said faggots should be killed. It was very distressing language."

Wardle asked the man to stop, as did another passenger, identified only as Adam. It was at that point the situation took a violent turn, the man turning on Wardle and Adam.

Another passenger got footage of the attacker yelling, "Don't compare me to a gay man, ever!" before going on the aggressive physically. Wardle shoves him back, but he was eventually able to do damage before he was fully subdued.

"He didn't hit me, but he went for me and I warned him that it wasn't a good idea," Wardle recalled. "I'm quite a tall guy. Adam was a smaller and easier target. He was punched repeatedly and eventually knocked out."

The incident occurred in late March, and last Friday Scotland Yard issued an appeal for the man's arrest, releasing images captured by CCTV cameras in hopes that someone recognizes him.

"I just want him caught before he seriously hurts somebody," Wardle said. "This guy needs educating. He can't think that he has got away with it. I refuse to let him think that he has got away with it."

He added that he stepped in because "nine times out of 10, people don't stand up to this."

"I have heard it all before, but I was concerned that there were other people on the bus. Usually in London no-one bats an eyelid. They would rather keep out it, which is really sad."

According to police, a total of three passengers were victims of the man's violence, and described him as "a black man with a shaved head and goatee beard wearing a smart blue suit, black shoes and grey scarf."

"The Met will not tolerate any form of hate crime and we strongly urge anyone who has been a victim of this sort of situation to call police and report it," said Detective Constable Sarah Bunting of the Met's Road and Transport Policing Command.