A Blunt Instrument was the fourth and last in the Superintendent Hannasyde mysteries. Georgette Heyer later formed a series based around the secondary character of Sergeant Hemingway. Although I haven't read any of the others, based on this book, it would appear that the detective character is actually a supernumerary. The police aren't bumbling but they exist to go down the list of most likely suspects, then to throw red herrings into the mix, before finally solving the case.
Heyer has been likened to Agatha Christie, but there, again, unlike Christie's Poirot and Marple series, there is not much emphasis on the detective. Christie's detectives are peculiar, out-of-the-box thinkers, with a vast experiential knowledge of human nature. Hannasyde and Hemingway plod through the facts. One is not necessarily the sidekick of the other, either, so there's no awestruck innocent who hares off after the red herring in order to play off against the brilliant detective who holds things close to his or her chest. ("Ah, Hastings, all will become clear, mon ami, if you will have the patience.")
Actually, that's an unfair characterization of Hemingway, who shows flashes of humor and gets in some comedic dialogue, especially playing off of PC Glass, the Bible-thumping, pompous constable who calls in the murder.
This book, more than anything, is an upper class romance wrapped around a murder mystery. (Although Christie's books also had strong elements of romance, it shared equal billing with the mystery.) While the detectives plod with both their techniques and dialogue, the other characters are highly individual, sharp and wonderful embodiments of "the usual suspects."
The dead body is played by Ernie Fletcher, a rich ladies' man. His household includes his sister, Lucy, a dithery, socially awkward and snobby spinster; and his nephew, Neville, who is by far the best character, by turns insouciant, irreverent, blithe, and mischievous. Debt-ridden Neville especially is a prime suspect.
Good old Uncle Ernie was not just charming to the ladies but underhanded in his dealings with them as well, as it turns out. He holds IOUs for gambling debts incurred by Mrs. North, a comely neighbor, whose husband would not countenance her indebtedness. Mrs. North does not know which would be worse, that her husband is jealous of Ernie or that he isn't. They, too, are prime suspects. There are other suspects and victims, one of whom begins as one and ends up as the other. All the elements of a classic mystery are at the ready.
The amount of dialogue irritated me at first. It took half the book before I stopped gritting my teeth whenever one of the suspects would start in to make a point. The point was usually obfuscated first by dithering, temporizing, and non sequiturs before being made. PC Glass with his Biblical quotes and dour looks irritated me the most. His superiors barely tolerated him, and I would have sentenced him to patrolling sheep pastures for wolves were I in charge.
By the second half of the book, however, I started to enjoy it. Neville and Sally, Mrs. North's sister and a "crime novelist," bantered charmingly and tolerated Mrs. North's attempts to be her own worst enemy. A lot of the peripheral characters appeared fully, even if they only had a paragraph or two to call their own.
There is certainly a charm, however dated, to this upper class play of morals, and I can see why Heyer was popular, even during England's depression and the years of war. This is just pure escapism.