Boxing-champ-turned-security-guard Julius Francis demolishes rabble rouser with punch

A man in London picked the wrong place at the wrong time to stir up trouble.

Julius Francis, a 57-year-old former professional boxer who was once the British champion and in 2000 fought Mike Tyson, is now a security guard at BOXPARK Wembley.

In the video, a man in a blue du-rag is seen repeatedly yelling obscenities at the security staff and other people who appeared to be workers at the venue, saying “f–k you!” too many times to count, and yelling, “I’ll f–k you up!”

Warning: violence and language

The man shoves multiple people as a group of security guards try to nudge him away from a set of guardrails around the space.

About 45 seconds into the clip, Francis unleashes an absolutely vicious right-hand, knocking the rabble rouser down with one of the most severe head-shots you’ll ever see in a viral internet video.

“When your mouth writes a check …” observed Sports Illustrated and DAZN boxing reporter Chris Mannix.

Mike Tyson and Julius Francis boxing in 2000. AFP via Getty Images

Facing Tyson in 2000, Francis fared only slightly better than his foe in this video. Not even a minute into the second round, Tyson won by TKO.

Nonetheless, should anyone have an inclination to start some trouble at BOXPARK Wembley, this video should dissuade that idea.