Dull dull dull. A formulaic tale of the police interviewing one bland suspect after another, the appearance of each one meticulously described, even if they exist only for a couple of pages. Not even the addition of a secret club for posh orgies, the 96 (geddit?) club, could spice up the book. Through the course of two murders and another attempted one, the police investigate through banal dialogue, with the narrative occasionally cutting to their PoV as well as the suspects' equally banal love lives (or lamented lack of them). It feels like PD James hopes to distinguish it from a run of the mill crime novel by trying to explore the psyche and backstories of the characters. However, there is not much depth or relevance to any of this and it merely bogs down the plot. Shame, since the premise is interesting: each killing is a replica of a 1930's murder. After several pages of more description, more talk, and too-convenient coincidences, I silently cheered whenever another body dropped.
The sad part is that there are some seeds of promise in 'The Murder Room,' but they never sprout. Kate, a subordinate Inspector, is a fairly interesting character and there is a hint of tension and strife with her snarky colleagues. But these are not developed. Instead, Kate is limited to occasional outbursts related to her working class roots and subsequent class rage, and usually is 'gently' chastened by the protagonist Inspector Dalgleish. (The latter is not only a clever, hardworking sleuth but also suitably genteel with a secondary career as a respected poet.) The moment before the killings which is written as if the narrator is looking over the shoulder of the unknown killer, is chilling and vivid. If only the rest of the prose could be so.
I'll be vague here to avoid spoilers: you can also see a strain of conservative thought running through the book, for at its heart is the idea of preserving institutions, loyalty as a result of ties of blue blood, and a subtle endorsement of deferring to the upper classes. This links 'The Murder Room' to the 'cosy crime' novels best exemplified by Agatha Christie's works, even though this book was published in 2003 and has crimes as graphic as those in, say, Scandinavian noir.
(Edited for typos.)