Hero Łukasz is seen on the left of the picture tackling armed terrorist Usman Khan along with other passersby. /Facebook

A Polish chef who tackled crazed London Bridge terrorist Usman Khan with a 1.5-metre-long narwhal tusk has been hailed a hero.

The man identified only as Łukasz was seen grabbing the tusk from a wall in Fishmongers' Hall where he was working before running outside to confront the attacker.

The kitchen worker then tried to pin Khan down with the tusk as the attacker stabbed at his hand.

Police say the 28-year-old Khan was already known to authorities, and was convicted in 2012 for terrorism offences before being released from prison on licence in December 2018.Fair use

A colleague of Łukasz told The Times newspaper: “Łukasz grabbed a nearby pole and ran at him, getting stabbed in the hand in the process but continued to pin him down.

“Being stabbed didn't stop him giving him a beating. Łukasz is a hero.”

Łukasz is thought to have suffered from cuts but is not critically injured.

In a tweet, bystander Amy Coop called Łukasz a hero.Amy Coop/Twitter

One man and one woman were killed by Khan, and several others were injured.

In a tweet, bystander Amy Coop said: “A guy who was with us at Fishmongers Hall took a 5' narwhal tusk from the wall and went out to confront the attacker.

“You can see him standing over the man (with what looks like a white pole) in the video. We were trying to help victims inside but that man's a hero #LondonBridge”.

The hero chef grabbed the 1.5-metre-long narwhal tusk off the wall before running outside to tackle Khan.GNU Free Documentation License

Police say the 28-year-old Khan who was shot dead by armed officers was already known to authorities, and was convicted in 2012 for terrorism offences before being released from prison on licence in December 2018.