An illegal rave has taken place in Norwich despite an attempt by police to confiscate sound equipment.
Norfolk Police said officers stopped two vans in the Fifers Lane area of the city on Saturday night which they suspected of carrying sound equipment.
As they tried to have the vehicles removed they were confronted by a crowd of 300 people who surrounded the vans preventing them from being moved.
Police withdrew at 2330 GMT to keep an eye on New Year celebrations elsewhere.
A Norfolk Police spokeswoman said officers have been monitoring the situation and intended to prosecute those responsible for the rave.
She said it had taken place in an empty building and most rave goers had gone by about 1400 GMT on Sunday.
The spokeswoman said officers had decided not to stop the rave because they had only received one complaint about noise and the amount of resources needed to stop it would not be justified.