Police have appealed for witnesses after a video of a man wielding a knife in one of Great Yarmouth’s main thoroughfares was widely shared on social media.

In the video posted on Twitter a man can be seen apparently shouting and then waving a knife outside a family restaurant.

It was captured by a teenager after eating at the Yankee Traveller, on Sunday November 18.

A police spokesman said: “Officers have been made aware of a short video taken by a member of the public which shows a man on King Street holding what is believed to be a knife.

“Whilst police did not receive any calls to our 101 or 999 numbers at the time of the incident, officers are now investigating the footage and are asking anyone who witnessed the incident to contact them.”

Insp Donald Dallas added: “We are still trying to establish the exact circumstances around this incident and anyone who may have witnessed it should contact police.

“We take knife crime extremely seriously and would urge any members of the public who witnesses anyone in possession with a knife to not delay and call 999 immediately.”

Courtney Gallant, manager at Liberty’s Public House, opposite the restaurant, said she had seen an increase in violence.

She said: “King Street is the place to be in Great Yarmouth at the weekend with all the clubs and bars, but I have noticed fewer people coming down. “People are scared to come into town: they don’t feel safe with the increase in violence.”

The footage was sent to police on Twitter after a concerned parent sent it to former UKIP county councillor Jonathon Childs.

Carl Asker, manager at King Street Traders, said that although business had not changed over the years, the nightlife had.

He said: “Business wise, in the day, things haven’t really changed. But at night I see a lot more gangs of people about. I can imagine for those who live here it can be scary.”

Anyone who may have witnessed the incident should contact PC Stephen Hughes at Great Yarmouth Police Station on 07989 300291 or call Crimestoppers anonymously on 0800 555111.