I am utterly stunned to see no other comments on this masterpiece.
Dennis Potter has, in the words of David Milch, "influenced everybody". Both Woody Allen and the Cohen brothers have quite blatantly stolen/borrowed from Potter (I am not bothered by this in the slightest). The currently running The Marvelous Mrs Maisel has a husband/wife writing team and the husband has said that Potter and the Singing Detective particularly are his lodestar in film writing and production.
I first encountered Potter and this series about 25 years ago when Canada's CBC ran it. The response of viewers was so strong that CBC decided to repeat episode 1 the next week for those who had missed it, followed by episode 2 the same night.
I don't know where, now, you can access this work online but you can surely purchase the series on DVD. Do so. You won't be sorry.