A television camera slowly zooms in on a small tree. For a moment, a man with an ape mask appears. He is carrying a billboard which explains that the tree will “speak” to the audience on the film-makers’ behalf. He runs off. A voiceover representing the tree begins to put forward slogans that make varying degrees of sense: “Use your birth certificate as a credit card” and “Aeroplanes are a substitute for levitation”. We are in the realm of deep surrealism.

Welcome to early 1970s British TV, and one of the most audacious and fascinating broadcasting projects from that time, now the subject of a new exhibition titled People Make Television at east London’s Raven Row gallery. The show celebrates the first 10 years of the BBC’s Community Programme Unit (CPU), and the Open Door programme, which allowed groups and individuals with “voices, attitudes and opinions” to make and broadcast programmes on, well, pretty much anything they liked.

The talking tree was featured in a 10-minute short from the Albion Free State group, a hippy eco-anarchist collective. But most of the 243 programmes that were made between 1973 and 1983 had more serious ambitions, and together they form a punchy commentary on a fast-changing, highly polarised time.

“One was never quite sure what one was going to get,” says Alex Sainsbury, co-curator of the exhibition. “Sometimes it was riveting and compelling, sometimes it featured material that didn’t quite know what it was . . . What you are watching is something that has its own grammar, and the deeper you engage with it, the more fascinating it becomes.”

The programme-makers included marginalised groups of all kinds, raising issues that are familiar in today’s cultural landscape — gender politics, immigration, neurodiversity — but which were largely neglected in the mainstream broadcasting of the time. “We cannot underplay how shocking it was to see what it dealt with, compared to what came before and after it,” says Matthew Harle, another co-curator.

The impulse to open up programme-making to the public, at a time when it was controlled by a professional elite, sprang from similar initiatives in the US, and a groundbreaking 1971 edition of the BBC’s Late Night Line-Up documentary series, in which a film of factory workers discussing the increase in the BBC licence fee was broadcast in unedited form. Their conversation included sceptical remarks over whether their views would be fairly represented, adding a layer of sophistication to the piece. Corporation executives (including director of programmes David Attenborough) could not help but be smitten by this vérité approach to news features.

What is most striking about the style of the films, many made on handheld Portapak cameras rather than the BBC’s preferred 16mm equipment, is the rawness. “The pacing is different, conversations go on for ages, all the rhythm of standard television is gone,” says Harle. Sainsbury adds that the programme-makers’ inexperience constituted a style of its own. “It is not seamless,” he says. “It is full of seams.”

The politics behind the films, more than 100 of which will be presented at the exhibition, are mostly from the left: trade union groups making pieces about their own working conditions, debates over feminist issues, radical housing associations voicing concerns over government policy.

But there are contributions from the other end of politics too: films were made by blood-sport groups and fringe Christian organisation the Campaign for the Feminine Woman. The theme of immigration gave the series its most controversial moment in 1976, with the airing of an episode by the British Campaign to Stop Immigration. That programme prompted a rebuttal in the form of a stinging polemic, It Ain’t Half Racist, Mum, co-presented by the cultural theorist Stuart Hall and actor Maggie Steed.

“Basically it is Stuart Hall doing cultural studies on TV, doing a close reading of [the 1970s sitcom] It Ain’t Half Hot, Mum, and essentially just shaking his head going, ‘I can’t believe this racist shit is being broadcast on TV’,” says Harle.

Hall’s incredulity is buttressed by further examples. In an extract from the Tonight current affairs show, interviewer Denis Tuohy is shown asking the American white supremacist David Duke: “What is your message to the people of Britain?” Duke replies: “One of the main things is that they are not alone, that there are white people all over the globe who sympathise with them”.

Another interview, by the BBC’s top political pundit Robin Day, is picked apart for the way in which he frames his questions in a show devoted to immigration. But that particular critique evidently touched a nerve. “Suddenly,” says Harle, “the CPU [Community Programme Unit] gets a letter from on high in the BBC saying, ‘I think you ought to apologise to Mr Day for broadcasting a programme criticising his interviewing style.’ You see the clout of these big BBC figures leaning on these tiny minority programmes.”

The CPU was commonly referred to as the “Communist Programme Unit” by non-sympathisers within the corporation. Running the CPU was a bit like “being a goalkeeper” says Harle. “If you did your job, nobody noticed you, if things went wrong, it was all your fault.” But the waspish reprimand over the Day incident was evidence of a subtle shift in the balance of power between programme-makers and their audience.

Ratings were hardly a priority for Open Door. While an episode by the Transex Liberation Group attracted an impressive 500,000 viewers, one by the Science Fiction Foundation failed to register above zero. After a decade of programming that veered from the bizarre to the earnest, Open Door was superseded by Open Space, a new, more structured show relying on a greater input from professional producers who were given a bigger budget for their efforts. Inevitably, some of the urgency and rawness was lost.

Another decade later came another incarnation, Video Nation, which ran from 1994 to 2004, when the CPU was disbanded by the BBC. By then, the work of the CPU had left its mark on the style of British TV. “During the 10-year slice that we have chosen to look at, there was the ongoing debate about a fourth channel, and the exhibition ends at the point when Channel 4 is founded,” says Harle.

Sainsbury adds: “Open Door was the test-bed of what a new form of television would look like. Channel 4 reflected the desire to get real people on television, which was written into its founding. The word ‘community’ is so overused, it has become a cliché, but here it was defined as a number of people working to make a film together.”

Today’s media landscape is now replete with the voices of real people, transmitted all over the world, loud and fast. But they don’t — to say the least — always seem to be harnessed to any wider social movement. Sainsbury says that Open Door provided “a model for participatory democracy, and a very eloquently expressed one, that we don’t see at stake in the social media now. Here were political ideologies being contested in a public space. It was a very exciting time.”

I ask if we should be nostalgic about the era. “Nostalgia is always wrong,” asserts Harle. “But if there is something that is missing now, it is this sense of monoculture, the idea of there being a shared space. This was a time before media bubbles, when television was switched off, when event TV happened. It was our companion in the evenings, in a way that it is not any more.”

January 28-March 26, Raven Row, London, ravenrow.org

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