Britain's police officers are infiltrating protests groups and acting as false witnesses in court.

An undercover police officer infiltrated an environmental group. Later, he took part in a criminal trial under a false name and lied under oath with due permission from the senior police authorities, it was claimed.

Jim Boyling, a specialist operations detective constable with the Metropolitan Police, maintained an alias, "Jim Sutton," throughout the court proceedings. The allegations have forced the postponement of the publication of a review into the future of undercover policing and the actions of another officer who infiltrated protest groups. The undercover officer went on trial for public order offences with other activists from pro-cycling campaign group "Reclaim The Streets" following a demonstration at the headquarters of London Underground in 1996, reported the BBC.

"It's institutionalised police corruption of the legal process for this to happen," Mike Schwarz, of law firm Bindmans. "This case raises the most fundamental constitutional issues about the limits of acceptable policing, the sanctity of lawyer-client confidentiality and the integrity of the criminal justice system."

The matter came to light following a review of records at Bindmans legal firm prompted by the case of another undercover officer, Mark Kennedy, who spent seven years infiltrating a group of climate change activists. The lawyer said the revelation raised concerns about the "confidentiality" of discussions between the officer's co-defendants and their legal representatives, reported the BBC.

Activist John Jordan, who was convicted of assaulting a police officer and given a conditional discharge after being arrested with "Jim Sutton," is appealing against the verdict following the allegations, the report said.

The review, launched by Her Majesty's Inspectorate of Constabulary (HMIC) has now been delayed.. A spokesman said: "Our report, 'Undercover Tactics in Public Order and Extremism,' was due to be published. However, in light of the allegations in the media, we are delaying this launch. This is so we can consider the relevance of this information to the recommendations for improvement in undercover policing tactics that we are making in our review. We will be writing to the Guardian and Newsnight to invite them to provide any additional information they may have on top of that is published."