T. S. Eliot called it, ‘the first, the longest, and the best of modern English detective novels’ – and I string along with T.S., here.

Often described as the earliest-ever detective mystery, the plot hinges around the theft of a flawed-but-famous Indian diamond by the Verinder family’s wicked uncle. He bequeaths it – basically, as a curse, for it ruined his own life – to his innocent niece, Rachel, as a method of revenging himself on his estranged sister. On the day of her receiving it… it disappears.

This is a tough book to review without giving away the plot, but the diamond’s allure has the effect of estranging practically everybody, including the volatile but charming Rachel and her ardent lover Mr Franklin. Other characters of note include a well-born male charlatan (preying on society do-gooders) and a do-gooder of elephantine self-importance (Miss Clack). There’s also Gabriel Betteridge, the elderly and devoted family steward, an apothecary with a tragic secret, and a passionate parlourmaid. Also memorable is the book’s mournful and curmudgeonly detective, Sergeant Cuff, with his unlikely passion for roses.

A bit reminiscent of Upstairs/Downstairs, of course and – necessarily – dated. And so… why do I love it?

I love Collins’ over-the-top narrators, for a start. The book has several. These include the self-deceived Miss Clack, busily strewing godly pamphlets around London, the worthy Betteridge – along with his pert daughter – the insightful apothecary and Mr Franklin, who is, in some ways, the hero. Their individual ‘voices’ are wonderfully and often hilariously well-rendered.

I also love Collins’ convoluted yet rhythmical style – and his sly asides. I love the respectful, liberal mind-set of an author who doesn’t patronise, not only the Victorian lower orders, but Indians and colonials either. I also love the pacing and the timing – the understated end is masterful.

 In short, it’s a book that repays inspection on style grounds alone, but – have to be honest – it’s the sheer entertainment value that draws me back. Like Dickens or Austen or P.G. Wodehouse, even when you not only know how it ends – even when you could describe every twist and every turn of the plot, it’s like revisiting an old friend – and remembering what you always loved about them.