To Who fans the saddest loss is probably The Tenth Planet part four (1966). The story, of which the first three episodes thankfully still exist, introduced the Cybermen and was first Doctor William Hartnell’s swansong. Other high profile casualties include all but one episode (two) of what was supposed to be the final end of the Daleks – Evil Of The Daleks (1967); the genuinely sinister Fury From The Deep (1967), where a thrashing weed creature tries to drag the Tardis crew to the depths of the ocean, and the Hammer-esque Web Of Fear, which had tons of atmosphere, introduced series icon Brigadier Lethbridge-Stewart and presaged the 70s action-packed Pertwee era with its contemporary Earth-bound tale of robot yetis invading London.

Doomwatch

Created by the partnership that thought up the Cybermen, Gerry Davis and Dr Kit Pedler, this early 70s BBC show was more science fact than fiction, basing its hard-edged stories of threats to humanity on genuine scientific concepts and advances. Out of its three seasons only series two is complete and it’s a great shame because many of the stories had eco-peril themes, such as rising seas, pandemics, lethal chemicals entering the food chain and, err, killer dolphins, which would surely resonate with people today. The biggest disaster episode-wise is probably the loss of series one finale Survival Code (1970), just for the shock value of killing off main character Toby Wren (Robert Powell) in a bomb blast.

A For Andromeda

If this seven-part serial, broadcast in 1961 and famous for being the big break for actress Julie Christie, had survived complete to this day, it might have seemed a little slow and wordy for our taste. Nevertheless A For Andromeda is first-rate sci-fi. That’s only to be expected, as the story – about a mysterious alien radio signal beamed across the stars with the sole purpose of subjugating humanity – was devised by noted astronomer Sir Fred Hoyle. Hoyle made a lasting contribution to scientific understanding, but thanks to the BBC, his contribution to science fiction television, which drew in an average audience of over nine million viewers, is all but destroyed. One episode, The Face Of The Tiger, was returned to the archives in 2005, and a few clips from other episodes remain, but it represents nothing more than a muted echo of the creative legacy of the man who coined the term ‘Big Bang’.