noir/not noir? plus John Williams and UK

I haven't posted in a while--I've been absorbed in John Williams's Cardiff trilogy (Five Pubs, Two Bars And a Nightclub; Cardiff Dead; and The Prince of Wales), which raises several questions for this blog. The first is that I have not yet dealt directly with contemporary noir in the U.K., since I've been concentrating on noir-in-translation from non-English-speaking countries. There is of course a wealth of crime writing in English (and numerous excellent publishing houses supporting that writing), and I intend to address that gap in my journal soon. Williams's books also raise the question of what kind of plot qualifies as noir. His trilogy deals with a criminal subculture in Wales (prostitution, gangland-style machinations, suspicious death, etc.), but there is no murder plot per se, and only a detective in a marginal way (Mazz, in Cardiff Dead, halfheartedly pursues a missing rock star on commission from a sort of gangster, but it's not essential to the main narrative). The atmosphere of the novels, though, is pure noir, and has a lot in common with the milieu of George Pelecanos's undoubtedly noir Washington novels. The Cardiff of Williams's books is in transition from a lower-class soup of races, underworld clubs and professions, and people living at the margins of society. What it's moving toward is the artificial "downtown" of so many U.S. cities--theme pubs, new developments, and the closing of institutions like the Custom House, a late-night bar favored by streetwalkers. The novels are actually about the city, and Williams employs a kaleidoscope of characters throughout the stories in the first volume and the 2 novel-sequels, each a particular angle on what's happening to the city in its transition. The result is a gritty realism that a focus on a single character could not provide, and Williams's writing is unfailingly interesting, lively, and engaging. So it's noir in a literary vein rather than a murder-genre vein, I guess. It would be interesting to have a discussion of the noir-or-not question with regard to Williams--perhaps there's a panel waiting to be convened on the topic?