A Brighton nightclub is suing Sussex Police for £150,000, claiming harassment.
Club Barracuda, in Kings's Road Arches, claims police trespassed and cost it revenue during a series of "illegal" raids.
Sussex Police said they would fight the county court action but declined to comment further.
The action follows a visit to the Barracuda, which claims to be the oldest private members' club in the town, by police in September, prior to the Labour Party conference.
Labour researchers were enjoying a private function when police arrived and brought the evening to an abrupt end.
The club's solicitors, Dakers Seymour, claim it was a raid carried out without a warrant and that doormen were warned not to work there any more.
The action temporarily forced the club to cease operating.
Edward Daveron, a club trustee, said the raid was one of a series which had forced the cancellation of 50 private parties through to April next year.
He said: "We cannot risk holding them knowing police could close them down."
Mr Daveron accused police of employing "bully boy" tactics and frightening staff and customers.
He said none of the raids resulted in arrests or drugs being found, there had been no violence and no one had been accused of not being a legitimate guest.
Mr Daveron first complained publicly about police action last year when the head of Brighton CID denied harassing the club.
Detective Chief Inspector Graham Davies said at the time: "There are 800 licensed premises and 40 clubs in the town and they all receive visits from police licensing officers as often as is necessary.
"Other clubs have been visited many more times than this one, a few on a weekly basis.
"This is to ensure they are being run in accordance with the regulations."
Mr Daveron is demanding the suspension of the police licensing unit and the "immediate intervention" of Chief Constable Paul Whitehouse and Brighton and Hove Council chief executive Glynn Jones.
He says he fears there is a conspiracy which could result in the council taking back the club's lease.
He said: "We need dialogue, to sit down round a table with senior people to talk about what is going on."
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