The invaluable Dangerous Minds posted about it, and has this to say about it:
What the fuck were these people thinking? What were they scared of?
Well, to start with, 1970s Britain was in a mess. It had high unemployment, 3-day working weeks, nationwide power cuts, tax was at astronomic levels, food shortages, and strikes were commonplace, and the Labor government feared a revolution was imminent.
To explain why this all came about, let’s rewind the tape to a mass demonstration at Grosvenor Square, London, March 1968. This was where an anti-Vietnam War rally erupted into a massive pitched battle between protesters and the police. Outside of the American Embassy 200 people were arrested; 86 were injured; 50 were taken to hospital, half of which were police officers. The Labor government of the day, were stunned that a group of protestors could cause such disorder, and near anarchy, that could have led (they believed) to a mini-revolution on the streets of London.
In fear of such anarchy ever happening again, the government decided to take action. At first, ministers considered sending troops out into the streets. But after some reassuring words from Special Branch, Chief Inspector Conrad Hepworth Dixon, they were convinced that the boys in blue could handle any trouble. Dixon was allowed to set up a new police force: the Special Demonstration Squad.
This was no ordinary police operation, the SDS had permission to be literally a law unto itself, where its officers could operate under deep cover, and infiltrate left-wing, fringe organizations and youth groups, with the sole purpose of working as spies and agents provacteurs. Harold Wilson’s government agreed to pay for this operation directly out of Treasury funds.
The SDS carried on its undercover activities against any organizations that they believed threatened Britain’s social order. This include animal rights organizations, unions, and anti-Nazi, and anti-racism groups. They were also allegedly involved in the planting incendiary devices at branches of department store Debenhams in Luton, Harrow and Romford in 1987; and one member was later involved in writing the pamphlet that led to the famous “McLibel” trial of the 1990s.
The workings of the SDS were on a “need to know basis,” and only a handful of police knew exactly what this little club were up to. But their presence fueled genuine fears amongst the British Establishment that there were “Reds under the beds,” and that revolution was a literal stone’s throw away.
This was all going on behind-the-scenes, while out front, muppets like the councillors and journalists lined-up on this program, pushed the hysteria of Punk Rock riots and civil disobedience, that reflected the very genuine fears at the heart of the UK Establishment. (Note London councillor Bernard Brook-Partridge mention of “MI5 blacklists.”)
And here's the vid of the show. Essential viewing.