Residents have spoken of their terror as hordes of people trying to enter an illegal rave threatened to overwhelm police before hurling bottles and vandalising police cars.
One police officer was injured as reinforcements were brought in to prevent people storming the site of the former Pinebanks leisure centre in Thorpe St Andrew last night.
Police said a member of the public reported cars and a van entering the site on School Lane at 11.50pm.
As officers secured the building, more people began to arrive via Harvey Lane and White Farm Lane, becoming hostile towards the police.
Extra police and a police helicopter were brought in to deal with a crowd they said was 50-60 strong.
Suzanne Sears, who lives in nearby White Farm Lane, said: 'They were like rats climbing over the gates trying to get into the place. There were hundreds of them. They all had plastic bags. They were out for a good evening.
'It was like the police could not cope with it. When I called the police they said 'We have got 15 units on the way'. The next thing I knew there were dogs barking everywhere. It was mayhem.
'I was terrified. I just could not believe what I was seeing.
'There were a few who were angry when they realised that what they had come for was not going to happen.'
Her husband Duncan said he slept through the disturbance, until his wife woke him to move the car.
Their daughter Gabby said cars were parked all around the surrounding area when she arrived home from work at 1am. She was unable to drive down White Farm Lane because of the crowds, and was given a police escort to walk home.
Bottles were thrown at officers using shield lines to keep crowds at bay, and from entering the building where sound equipment had been seized.
At 12.34am, police turned to social media to discourage more people from arriving, tweeting: 'thinking of attending a rave in #norwich? don't bother it's not happening! police at scene.'
Officers managed to hold off the crowd, which began to leave the site at around 1.20am, with people moving off into the residential area. Police continued to monitor their movements and the incident was brought under control within two hours.
An investigation has been launched and detectives have arrested 12 people.
Chief Superintendent Bob Scully said: 'This was a serious incident and while nearby residents would have been disturbed by police activity an illegal music event running throughout the night and into the early hours would have caused more impact on the local community.
'The action taken last night to shut down this event falls in line with our efforts to reduce serious anti-social behaviour and environmental damage caused by illegal and unlicensed events.'
Were you affected by the rave, or have any photos? Phone 01603 772468 or email martin.george@archant.co.uk
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