Q&A: Undercover police officer
What's the issue?
An undercover police officer has been accused of taking part in a criminal trial under an alias, calling into question the safety of a conviction.
Detective Constable Jim Boyling infiltrated an environmental protest group and was arrested charged alongside its other members. In 1996, he gave evidence as "Jim Sutton", the identity he had assumed when he went undercover. Det Con Boyling/Sutton was acquitted along with other protesters. But one activist John Jordan was convicted of assaulting a police office.
Can a police officer do what DC Boyling did?
A fair trial depends on three principles in English law: the giving and receiving of confidential legal advice, giving truthful and accurate evidence in court, and an obligation on the prosecution to fully disclose relevant material to the accused so they can mount a full defence.
On the face of it, an undercover officer, maintaining a false identity and taking part in confidential legal conferences with those he is investigating, undermines the first two. If any of this investigation forms part of the evidence, then it would undermine the third element of a fair trial.
Lord Ken Macdonald, the former director of public prosecutions, told the BBC: "You don't send police officers into court to lie about who they are, about their identity, about what their role is in a series of offences.
"You don't send them into solicitors' offices pretending to be defendants and being party to confidential legal conferences. They've crossed a line and it's a serious, serious issue."
In other words, there would be very strong grounds to appeal a conviction.
Would the officer have broken the law?
There are two key offences that could have been committed: Perjury - lying under oath - and perverting the course of justice. If the officer had the agreement of a superior, they could be charged with conspiracy.
What rules was Jim Boyling operating under?
The basic legal principles covering surveillance operations did not begin to be codified until the year after he was arrested.
The Police Act 1997 gave the police and other law enforcement agencies permission to break into property for surveillance operations. Three years later came the Regulation of Investigatory Powers Act (Ripa) and its Scottish equivalent - the first time that undercover operations had been regulated.
Police forces and other agencies ran undercover operations before Ripa on the basis of guidelines from inside their own organisations and the Home Office. The government had to codify these rules into a clear law so to make operations compliant with the Human Rights Act.
So could an officer today lie under oath?
Nobody can lie under oath in court. There is nothing in law that allows a police officer or anybody else to claim that they had a reasonable excuse to do so.
Who runs undercover officers?
Undercover operations are older than policing itself - monarchs in Tudor times ran agents to infiltrate their enemies. Today, undercover officers can be deployed by police forces, the Serious Organised Crime Agency and, naturally, MI5 and MI6. Surveillance laws are often misunderstood. Local councils cannot deploy an officer to live undercover next door to check you are putting your recycling in the right bin - it would not be proportionate.
What does this mean for future police operations?
HM Inspectorate of Constabulary had completed a report into undercover operations in the wake of revelations about Mark Kennedy, the alleged agent provocateur who played a role in demonstrations against a power station.
That report has been pulled and the watchdog wants to see if the new information about Boyling affects its conclusions.