Former British boxer Julius Francis appeared to one punch KO a rowdy outside BoxPark in Wembley.
The incident, which went viral on Twitter, showed an altercation between a group of men and security personnel.
One person in particular starts to get angry and seems to become aggressive.
But as he begins to move towards Francis, who is stepping back, the ex-combatant lands his right hand, dropping the man.
Met Police said: “Police are aware of footage circulating on social media showing an incident involving security personnel and a member of the public outside Boxing Park in Wembley.
“An investigation into the circumstances, including establishing the identity and well-being of those involved, is ongoing.
“There have been no arrests and investigations are ongoing.”
Francis, now 57, won 23 of his 48 fights and lost to boxing legend Mike Tyson in Manchester in 2000.
He won heavyweight belts during his career, including the Commonwealth and British titles.
The Londoner last boxed in 2006 and after retiring founded a fitness company while working as a security guard.
The Sun has reached out to BoxPark for comment.
https://www.the-sun.com/sport/5555774/julius-francis-mike-tyson-security-officer/ Ex-Heavyweight Champion Julius Francis, who KOs Mike Tyson, the one-punch rowdy man, in his new job as a security guard