Three solicitors were today suing police for wrongful imprisonment after falling foul of strict prison regulations.
The trio were among five held at Brixton prison, in south London, in a mix-up over which lockers to use for their personal possessions.
They have launched a challenge against the Metropolitan Police claiming officers held them illegally and interfered with privileged legal papers.
The move comes a short time after Commissioner Sir Paul Stephenson said police should have more protection from expensive law suits.
The top officer complained about the cost and bureaucracy of civil cases brought by members of the public and of employment tribunals initiated by staff.
Jules Carey, of Tuckers Solicitors, who is representing the solicitors, said they were caught out after the rules changed about what should be stored where.
He said: "It is also unlawful and wholly unacceptable to remove confidential professional material from solicitors.
"I have today filed claims on behalf of my clients' for false imprisonment and the unlawful interference with their legal files with the Met Commissioner and HMP Brixton.
"I sincerely hope that their bail conditions will be cancelled, their DNA and fingerprint records will be destroyed and that they will receive a forthright apology from the Met and the governor for the ordeal they endured."
The five solicitors were arrested when police were called in by prison staff who discovered voice recorders and memory sticks were in the wrong lockers.
One of them, Simon Jowett, 39, said he was held for almost four hours before being released on bail.
He told the Evening Standard: "We were treated like criminals. Nowadays an arrest, even if no charges are brought, stays with you forever. This has put my reputation at stake."
Jim Meyer, of the London Criminal Courts Solicitors Association, said the case "beggars belief".
He added: "Criminal lawyers work with a strong sense of civic duty and commitment to justice.
"It beggars belief that the prison and police authorities in this case thought it was in any way appropriate to arrest these solicitors as they carried out their professional obligations.
"At face value these arrests constitute an affront to democracy, or are the result of rank stupidity, or both."
A Metropolitan Police spokesman said: "We can confirm police were called to HMP Brixton at about 2pm on September 21 after officers were contacted by Prison Service staff.
"Five people were arrested on suspicion of entering a prison with prohibited articles and they were later released without further action."Reuse content