A group of men were caught on camera breaking two boats off the riverbank with "frightened" holidaymakers on board.
It happened at around 2.20am on Tuesday, June 29, at the Norwich Yacht Station in Riverside Road.
CCTV---Boats-untied-from-Norwich-yacht-station
CCTV cameras spotted the four men walking along the road, before two of them bend down to untie one of the moored up barges.
The vessel can be seen floating out into the river as the two pranksters walk away, followed closely by two others.
Norfolk Police's Broads Beat team released the footage and announced it had conducted extra patrols on Tuesday evening.
A post on social media said: "Hi-vis reassurance patrols along the River Wensum in Norwich after the England match following anti-social behaviour with two boats untied from Quayside at the yacht station, frightening holidaymakers on board.
"Thankfully this is very rare but still a dangerous prank and a byelaw offence."
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