Created by Sir Clive Sinclair and his team, the ZX Spectrum hit the high street in April 1982.
It followed the hugely successful, if more technically-limited, ZX81, which had been many people’s first encounter with home computing.
The ZX Spectrum’s games were downloaded via a cassette player and displayed on a TV screen – and they were in colour, unlike its monochrome predecessor.
It cost £175 for the 48k model and £125 for the 16k version, which put it on many Christmas wish lists.
“If you go back a few years to the 1970s, you’ve got a time where home computers didn’t exist,” said Anthony Caulfield, co-director of the new documentary.
“Computers were in mainframes with air conditioning and cost many millions of pounds or dollars to create.
“The whole concept of having a computer in your home was a completely new thing.”