A former judge was jailed for three years today after he was caught in a "TV sting" coaching a man who confessed to be a criminal on how to get out of drug charges he was facing.

David Lancaster, who served as a Commander on the Royal Yacht Britannia when he was in the Royal Navy, was told that he "broke every rule in the book in a breathtaking display of unprofessional conduct" by a judge at Exeter Crown court.

Lancaster, who had been a solicitor for 14 years, a stipendiary magistrate for four years, and a court martial judge advocate for 11 years, was contacted by Neil Ansell, an undercover journalist, posing as a client who had been named as the supplier of a wrap of cocaine by a friend and arrested by the police.

Lancaster then attempted to incite Mr Ansell, a journalist with the BBC TV's Inside Out programme, to pervert the course of justice, the court heard, by providing him with lies that would get him off the police charge.

Peter Blair, QC, for the prosecution, said that during an appointment at his office, Lancaster invented stories that could be used when Mr Ansell went back to the police to answer bail. Mr Ansell told the jury that he made it clear to Lancaster that he was planning to admit supplying the drugs.

"He said not to worry at all, I would walk away, no problem," said Mr Ansell, who had a concealed microphone and camera during the interview with Lancaster.

Judge Graham Cottle told Lancaster that the criminal justice system in this country was held up as a model of fairness and good practice, and in order to maintain that reputation it was of paramount importance that professionals involved in the system behaved at all times with honesty and integrity.

"It follows that if any member of the legal profession engages in behaviour that brings the system into disrepute, he threatens the deserved reputation of the criminal justice system, and this necessarily has an impact on fellow professionals.

"Your behaviour in this case totally undermines that deserved reputation," said the judge.

The judge said that the BBC set up the undercover operation to see if what they had been told about Lancaster was true.

"Depressingly, the information was completely accurate," said the judge.

He told Lancaster, who was dressed in a pinstriped suit: "I have no alternative but to make an example of you in the interests of maintaining professional standards in the administration of the criminal justice system."

Lancaster had denied attempting to incite another to pervert the course of justice, namely a police investigation.

Earlier, defence counsel Patrick Gibbs QC told the judge that having built a reputation in the Royal Navy, in the law and at the bar, Lancaster had then destroyed it.

John Revell, the chief crown prosecutor for Dorset, said after the case: "Defence lawyers have an important role to play in the criminal justice system, and the great majority of people do their work professionally and properly.

"David Lancaster did not, and this was an appalling breach of professional standards; he acted totally improperly and dishonestly.

"The advice he gave deliberately provided a person he believed at the time to be a criminal with a number of lies to cover his illegal actions, with the intention that the person would give them to the police in order to beat the system."

Detective Inspector Adam Price, from Hampshire Constabulary’s Serious and Organised Crime Unit, said: "We expect defence solicitors to maintain high standards of integrity.

"By his own admission, David Lancaster’s behaviour fell far below what one would expect, both professionally and ethically. His criminal acts were designed to frustrate the prosecution of a person posing as a drugs dealer, who had worked with vulnerable children."

Times Recommends

• The Times celebrates its 225th birthday
• Heath discussed IMF loan during 1974 crisis
• Britain’s loneliest café opens for business