"[1] Counterstrike was originally proposed to the BBC in 1966 and a theme tune and effects were produced, but the project was shelved due to the airing of the US import series The Invaders on ITV, which had a similar premise.
"Out of Mind", the sixth episode, was cancelled on the night it was due to be shown and was replaced by a documentary on the Kray brothers who, on the same day, had been refused leave to appeal against their prison sentences.
"Out of Mind" was, for unknown reasons, never rescheduled; it remained unscreened and was subsequently wiped from the BBC Archives, thus making it one of the rarest pieces of British science-fiction television.
"King's Gambit", "Joker One", "On Ice" and "Nocturne" still exist in the BBC Archives as 16mm black and white film telerecordings, while the remaining five transmitted instalments "Monolith", "The Lemming Syndrome", "Backlash", "All That Glisters" and "The Mutant" – are listed as missing by the Lost Shows website.
[3] Episode descriptions are from the Radio Times[4] Two apparently respectable businessmen, running an electronics factory, are investigated by a journalist called Simon King.
And Simon, of all people, appears to be helping them... Three scientists are mysteriously lost on a sledging party that set out from a polar research station.
In a period of student riots, strong calls for a return to ' law and order' are made by General Falcon, a blood-and-guts commander of the Korean war.