The Singing Detective was created by Dennis Potter and originally ran in 1986 in Britain. I think it came over to the US a year or so later. I have a vague memory of watching some of it, and certainly there was a lot written about what a great series it was, with the usual note of "British TV is just so much better than American network crap." Looking back, I think it's kind of a Ur-British Drama, not in the "Upstairs, Downstairs" sense, but in the sense of it influencing modern American series like "Sopranos" and "Mad Men," ones with complex characters and layered stories. Watching these episodes has been a great lesson in storytelling. The main character, Philip Marlowe, is in a hospital ward with psoriatic arthritis. He drifts back and forth between past and present, sometimes imagining a 40s-style noir detective story (he's a writer), sometimes caught in his own past. Sometimes the threads mingle, with fictional characters talking to non-fictional. Sometimes everyone in the ward bursts into song. But each vignette is tight, clean-cut, meaningful: the characters emerge in their full complexity. You feel pity for Marlowe but you can see he is the author of some of his own misfortunes. He can be gratingly, glaring wrong but he's a human being.
When The Singing Detective was originally on I didn't see too much of it. I think it was on at a bad time and perhaps I came in in the middle of the series and didn't understand what was going on. One of the things I did love was the songs. I think the first time I ever heard the song "Ac-cent-u-ate the Positive" was in the link attached below. I thought it was fantastic -- I'd never seen anything like it.
I definitely recommend watching the series, for anyone interested in good storytelling or just good drama.