DCI Tony White was in charge of the investigation

The men were suspected of involvement in a ring that made �30,000 profit a week by selling heroin in Grantham.

Judge Michael Heath said officers recorded the conversation at Sleaford police station.

He said police had then not told him the whole truth in an attempt to cover up the bugging.

Deliberate police bugging of privileged conversations between solicitors and an accused is outrageous Judge Michael Heath

Judge Heath condemned the actions as "a fundamental breach of human right".

Lincoln Crown Court heard the senior officer in the case, Detective Chief Inspector Tony White, had been involved in a murder trial that collapsed for the same reason.

Knowing that, his colleagues later tried to "airbrush out or surgically remove" him from the drugs case when the bugging was exposed, said Judge Heath.

Branding their evidence "incredible", he added: "Deliberate police bugging of privileged conversations between solicitors and an accused is outrageous.

Operation Galaxy

"I am driven to the clear conclusion that there was planned and deliberate capture of privileged information between a solicitor and his client.

"This is not a case of a chapter of accidents or a comedy of errors. It is plain that I have not been told the whole truth by several police officers."

The judge made his ruling at the end of a preliminary hearing into whether the case against the alleged dealers should be allowed to proceed.

This cannot and will not happen again Lincolnshire Assistant Chief Constable Peter Davies

Those arrested were taken 20 miles away to the police station in Sleaford where the cell passageways and exercise yard had been bugged, the court heard.

This action breached the Police and Criminal Evidence Act allowing an accused to consult a solicitor in private at any time while held in custody.

Judge Heath ruled that it also contravened the European Convention on Human Rights.

Proceedings against the men, all from Grantham and aged between 23 and 50, have been stayed.

Lincolnshire Assistant Chief Constable Peter Davies later insisted the case had originally been the result of "diligent intelligence-led police work".

Mr Davies said there has since been a thorough revision of procedures to ensure the issues that led to Thursday's judgment cannot be repeated.

"In short, this cannot and will not happen again," he said.

Corley case

The earlier incident involving illegally-taped conversations happened during the questioning of five men accused of murdering Lincolnshire man Mark Corley.

The case collapsed in January 2002 after the illegal taping was uncovered.

Mr Corley was found murdered on remote farmland near Darlington, County Durham in December 2000.

The five men were charged with conspiring to kill Mr Corley, a convicted robber from Grantham, who was shot in the back of the head.