There's also an excellent old BBC dramatisation of this - and a few other good dystopian sci-fi's as part of the same strand called "Out of the Unknown". "Lev

There's also an excellent old BBC dramatisation of this - and a few other good dystopian sci-fi's as part of the same strand called "Out of the Unknown". "Level Seven" and "Tunnel Under the World" are especially memorable. https://en.wikipedia.org/wiki/Out_of_the_Unknown https://en.wikipedia.org/wiki/Out_of_the_Unknown