Interviews with Steven Spielberg, Ridley Scott, George Lucas and James Cameron – the ultimate blockbuster sci-fi directors – connected 50s movie clips in  “Keep Watching the Skies,” broadcast  in the UK on the Sci-fi channel this afternoon.

This could have been unwatchably dull. It turned out to be an excellent programme. The clips were well-ordered to present a narrative about early sci-fi. The uniformly - if oddly -white-bearded directors discussed the films that had influenced them as children. In the process, they explained a lot about the ideas and references in their movies, as well as contributing to a coherent argument about  how postwar sci-fi films reflected the social and political fears and hopes of the time.

For example, there was a fascinating bit where Spielberg discussed a film in which a group of kids were the only ones to see and communicate with a benign alien, which showed where he’d got the inspiration from ET and explained part of what he was trying to express in it. (Sorry, I wasn’t taking notes. I didn’t catch its name.)

The directors drew parallels between the two movie approaches to aliens – either childlike innocence repaid with evil, as in War of the Worlds, or human suspcion of outsiders, which leads to unnecessary wars against the Other. Inevitable comparisons were drawn with the expansion of Western cultures and the way the West reacts to the Third World .

There were a few unconvincing moments that I’m just putting in here to tone down the effusive raving. It’s hard to accept that even the most obsessive movie-goer could remember so much about their responses from 50 years ago. These directors could discuss scene details that their 6 year old selves allegedly noticed better than I can remember the broad plots of a quarter of the films I saw last year.

George Lucas claimed that his Star Wars robots owed nothing to Robbie the Robot in the Forbidden Planet, despite his admiration of the film, but was based on Fritz’s Lang’s Metropolis. This kept to the film directors’ union rule 43 – “A director must always reference at least one 1920s art film as an influence.”  This reference would be convincing from the director of Tron (a real nouveau Metropolis.) It beggars the imagination to connect R2D2 with the Metropolis robot images I have. Lucas’s words were undercut by being voiced shortly after a clip from the Forbidden Planet, where Robbie the Robot looked and acted exactly like R2D2’s big brother. (My bad here, it has occurred to me too late that he may have been referring to C3P10, which i suppose is a bit like a Metropolis robot. However, I am not going to spoil a good criticism, just because it’s contradicted by the facts.)

The movie clips were great. It had the seminal scenes from  movies which would be probably too boring to watch all the way through – now we’ve got used to better special effects and sci-fi that’s not shot mainly in a studio. They were connected in a way that gave me a deeper insight into the effects of their social context (fear of nuclear war)  than the tiny predictable sci-fi section of a Film course that I did at university x years ago.

Basically, it was a programme that had the acknowledged geniuses of mass-market sci-fi paying homage to their influences. It made you want to look at the originals and to reconsider the sci-fi from the 70s. It being on SciFi Channel, it will be repeated to death – it’s probably already been on a dozen times. It’s well worth watching out for.