This series was first shown on peak-time on Sundays on B.B.C. 1 (the prime channel) and regularly attracted audiences in millions including a precocious ten year old (me!) and his siblings. The reason was simple: it was the best adult oriented S.F. drama series the B.B.C. had ever made. They have never made anything better since. And it was very powerful, very realistic, completely believable, terrifyingly accurate and very scary on a psychological "what if?" level. Characters behaved in the way that people behave in real crises (such as civil wars) when the veneer of civilisation falls away: some try to grab power, some become natural leaders, some want to be led, others give up in despair and kill themselves. The series didn't flinch from showing all that or sugar coat the pill - and was much the better for it. The B.B.C. had the pick of the best T.V. and stage character actors around to cast it, plots never plumbed the depths of cliche, stories and themes were rarely if ever neatly resolved. It made a huge impact on the British national consciousness: episodes were being talked about in offices, factories and school playgrounds for days afterwards. If you consider that it was broadcast before anyone had ever heard of A.I.D.S., H.I.V., B.S.E., C.J.D. or G.M.O.s then I think it fair to say it was way ahead of it's time. And, sadly, like a lot of the finest T.V. produce of the B.B.C. and independent T.V. in Britain of the 1970s and 1980s - nowhere is it available on video.