British TV dystopias

I'm intrigued by the fact that series with the premise "in the future, our country is a quasi-fascist dystopia" are common enough on British TV, especially in the 1970s and 1980s, that you could call them a sub-genre. (I've just started watching one such show, The Guardians, which so far is excellent.) By contrast, I can't think of single example of this premise on US television, from that period or in fact ever.

Cultural difference? Or am I just not remembering US examples?