Tremendous stuff, the commentary and supplementary material to "Singing Detective;" I usually don't listen to commentaries (life's too short) but couldn't resist here; as I suspected, a lot of Potter's life went into his work.
Like the fact that he was sexually abused as a child. His mother had brought him to London (much like Marlow in "Detective") to live with some relatives; and he was bunkmate to a gay uncle who fellated him at night. Now we know where some of his horror of sex comes from.
Also, the fact that Potter had essentially dropped the detective story thread in the first episode, but that Amiel asked him to rewrite it, and he did in seven weeks in what Amiel describes as "the most extraordinary act of creation I've ever seen." The thread now has a more complex relationship with Marlow's real life now, and I suspect (haven't heard the commentary on disc 2) provides the basis for the show's surreal climax.
Producer Kenith Trodd I think (or was it Jon Amiel, the director?) also notes that you can be indifferent or combative towards Potter, but the one thing he can't stand is sympathy; that really infuriates him. We're talking one spiky son of a bitch here.
Interesting, but Amiel and Trodd point out the godlike qualities of Bill Paterson's psychiatrist. Maybe the character does stretch credulity (Potter's actual experience with psychiatrists was far less successful), but how many government-paid therapists out there have the intelligence and will to handle a Marlow, much less Potter? Think of him as Marlow's sounding board, the way writing "Detective" was Potter's, and think of Marlow as, in effect, performing therapy on himself. I think it works that way.
Trodd and Amiel confirm something I also suspected--that Potter came to rock music late in his career, and that this never had the emotional resonance that the songs of the '30s and '40s he grew up with had for him. Not that those songs are better than rock 'n roll per se; it's his obsession with them that gives them much of their power (and which is why the screen version of "Detective," which uses rock, marks it as late Potter, and not on the same level as his earlier work).