The UK Undercover Policing Inquiry was hearing evidence from a former police officer on Thursday when the feed was abruptly cut after he started talking about the role of the government’s domestic spying agency, MI5, in smearing political activists.

An inquiry into the conduct and activity of undercover policing in the United Kingdom from 1968 to 2008, commonly known as the ‘Spy Cops’ inquiry due to it having been set up over a decade ago in response to claims about police officers entering romantic relationships with female left-wing activists, is hearing evidence from its first former undercover police officer on Thursday.

Trevor Morris is a former undercover police officer who had used the recycled identity of a dead child to present as Anthony ‘Bobby’ Lewis, a disc jockey and German translator when infiltrating left-wing and activist groups in the early 1990s. As revealed by documents published by the inquiry, Morris takes strong exception to the criticism levelled at the Special Demonstration Squad (SDS) undercover unit, arguing it saved countless lives and prevented much disorder by infiltrating radical groups.

While the SDS infiltrated dozens of groups in the decades of its existence until its role was taken over by the National Domestic Extremism Unit in the years following 2008, one of the cases which has grabbed most attention is that of the campaign for Stephen Lawrence, a black teenager who was murdered in a racist attack in 1993. It has been alleged for years that undercover police officers who infiltrated the Lawrence Family Campaign had tried to find “dirt” to “smear” them.

Questioning inevitably turned to this during evidence-hearing on Thursday, and while former undercover police officer Morris totally denied the police tried to smear activists, he clearly implied other branches of government did so. He said: “nonsense. That’s not what we’re about, we’re about gathering intelligence, not smearing individuals. That’s a Security Service job, let them do that. We’re about gathering intelligence, that’s what we were doing.”

Apparently realising what he’d said, the police officer quickly followed up by remarking: “Sorry, I shouldn’t say that… let’s scrap that last bit, I’m not saying that”.

David Barr KC, lead counsel to the inquiry, then started to ask a follow-up question before the live-feed, broadcast on a ten-minute delay to allow for such moments, was cut. He asked: “Just to be clear, are you or are you not in a position to say whether or not the Security Service was seeking to sm-“.

The feed returned some 45 minutes later with the chairman of the Inquiry, retired High Court judge Sir John Edward Mitting warning the journalists in the room not to report what had been said during a period of time when the cameras had been off.

Sir John said, in sombre tone: “before you resume, may I say to those behind that there is a purpose to these orders. I know that you have complied with them up to now. They are serious orders, they do have a potentially serious consequence if they are breached. Please, I ask of you as well as demand of you, comply with what the order requires you to do. A transcript in due course will be published, which will contain part of that what was said between the hours of 11:16 and 11:22, but only part of it”.

Of these orders, the Inquiry official website notes: “These restrict certain information from being disclosed or published. They are issued by the Chairman and are legally enforceable.”

While a short break had been programmed in during the morning session, the camera was off considerably longer than the 15 minutes advertised, and the feed was taken down mid-sentence as the counsel spoke.

“Security Service”, as referred to by witness and counsel, is the formal name of the British government’s domestic spy agency known commonly as MI5, deriving from its origins in the Great War when it was known as the Directorate of Military Intelligence, Section Five. Per MI5’s own reckoning, their mission is to: “[protect] the UK against threats to national security… We carry out investigations by obtaining, analysing and assessing intelligence, and then work with our partners to disrupt these threats.”