I remember being hugely impressed by this when it was on TV a few years ago, and re-watching the DVD was not a disappointment. This is a beautifully acted and produced story of unrequited love, loneliness and melancholy. It poignantly conveys anguish, yearning and despair and is the darkest of dark dramas - there is no humour, no redemption, really no hope of any sort. Clearly not something to watch when depressed or for light relief, but it has extraordinary beauty and delicacy and is, along the way, very evocative of inter-war working class London. I haven't read the books it is based on, but I have read Hamilton's Hangover Square which touches on some similar themes and must be one of the bleakest books ever written.
There is hardly a false note in the drama except perhaps the rapidity of Jenny's fall in the second section. Despite her experience of being debauched whilst drunk by a heartless socialite it wasn't clear why she could not have resumed the threads of her life, instead descending into alcoholism, prostitution and her cruel treatment of Bob. So this moment in an otherwise immaculately paced drama felt rushed. I think we needed to see the next few days of her life to understand her - but whether this is a fault of the adaptation or of the original books I don't know. Otherwise, flawless.