After the broadcast of Curtis’s 2007 film The Trap, which traced the influence of game theory – the idea that humans behaved as self-interested individuals – on contemporary economic thought, Prospect magazine’s Max Steuer argued that the series “greatly exaggerates the power of ideas, and at the same time almost wilfully misrepresents them”. Others made similar criticisms of All Watched over by Machines of Loving Grace, which linked the anti-state philosophy of Ayn Rand with the “techno-utopians” who developed modern computing. At the very least, don’t his films encourage precisely that gloomy feeling – a sense that power is in the hands of an unaccountable elite – that so exercises him?

“Well, I am a creature of my time,” he concedes. We’ve found our way to a café in the shopping centre near Thamesmead, where we can chat at greater length. “What I’ve been trying to do is analyse why progressive ideas failed.

“Secondly, I’m interested in telling stories, because I like telling stories and I think ideas are important. I take particular influences of particular groups of people as a way of showing how that idea spread out. I never say this is where it all came from, this shadowy group of people. I’m telling you a story, like a novelist would, but as a factual story to try and bring it to life to you.”

The photos were stored with remarkably high fidelity on the tapes, but at the time had to be copied from projection screens onto paper, sometimes at sizes so large that warehouses and even old churches were rented out to hang them up. The results were pretty grainy, but clear enough to identify landing sites and potential hazards. After the low-fi printing, the tapes were shoved into boxes and forgotten.

They changed hands several times over the years, almost getting tossed out before landing in storage in Moorpark, California. Several abortive attempts were made to recover data from the tapes, which were well kept, but it wasn’t until 2005 that NASA engineer Keith Cowing and space entrepreneur Dennis Wingo were able to bring the materials and the technical know how together.

When they learned through a Usenet group that former NASA employee Nancy Evans might have both the tapes and the super-rare Ampex FR-900 drives needed to read them, they jumped into action.