Broken Homes, By Ben Aaronovitch. Gollancz, £14.99

London is, like all cities, made up of layer upon layer of story, and not all of those stories are about the real and mundane. The Matter of London has for a long time been a staple of the literature of the fantastic. Among the hipsters and banksters, the rich and the poor, it is a city where shamans and wizards seem plausibly our neighbours.

In recent years, the London Fantasy novel has become one of the more interesting sub-genres. Ben Aaronovitch's Rivers of London sequence does this better than most, and is in some ways the most thoughtful of all. Broken Homes is the fourth of his magical police procedurals: the most inventive and emotionally involving yet.

For a long time, Nightingale was the last vestige of the magical section of the London police; indeed, one of the last wizards, as the result of wartime events when the magic workers of the Allies and the Axis had their last, mutually fatal, duel. Now he has two apprentices, Peter Grant and Lesley May. Lesley is slowly recovering from having most of her face ripped off in her first overt encounter with the magical world. Peter, Aaronovitch's narrator, seems to have fallen particularly foul of the mysterious Faceless Man, Nightingale's Moriarty, but has also developed a strong working relationship with the goddess of the Thames and her many daughters.

Aaronovitch has involved his squad with the theatres of Covent Garden, the clubs of Soho and the Underground; now, he takes us south of the River. Here, it's all about architecture. Those who are sceptical about the massive Modernist housing estates of the Fifties and Sixties as liveable environments will be made to think again – what if some of those architects had entirely other agendas?

As always, Aaronovitch is intellectually witty and often delightful in his sparky dialogue. He knows that his characters have to be put in serious jeopardy: this book includes a particularly devastating twist whose emotional logic is overwhelming. Aaronovitch is never less than entertaining, and here he proves he can break our hearts as well.