Peter Grant is just a rookie cop in the Metropolitan Police Service when he discovers an aptitude for magic, and is taken on as an apprentice wizard. As he comes to realise the complicated supernatural life that infuses London, he is caught up in a case involving a malicious vengeful spirit. A spirit who is twisting the lives of ordinary Londoners and leaving a trail of nasty deaths in its wake. Peter has to learn the magic trade quickly before he and his colleagues becoming part of the game.

Anyone who has enjoyed Neil Gaiman's Neverwhere, Kate Griffin's Matthew Swift novels, Mike Carey's Felix Castor series - anyone in those shoes will adore Rivers of London. This novel takes the very essence of London and distills it into book form - to the point where I was delighted at being able to picture exactly where Peter is performing his investigation. There is even a mention for Forbidden Planet on Shaftesbury Avenue that made me literally go 'oooh!' as I was reading.

The language is clever and funny - Peter's narrative voice is full of wry asides and observations. I laughed a number of times, and smiled more, such as when Peter is practicing throwing fireballs: "We did an hour of practice, at the end of which I was capable of flinging a fireball down the range at the dizzying speed of a bumblebee who'd met his pollen quota and was taking a moment to enjoy the view."

Peter and his various colleagues and friends are exceptionally winning personalities, and I enjoyed reading about their mishaps and challenges. Favourite by far were the various Rivers of London, which, in this novel, take corporeal form. For instance, Beverley Brook is one of the daughters of Mother Thames, and is a capricious and mischievous teenager, looking for fun and attention.

I loved the way that Aaronovitch brought in folklore and explored much of the history of London without seeming to lecture. This includes the moment where Beverley reveals that the Fire Brigade are sailors: " 'Not now,' she said. 'But in the old days when they were looking for disciplined guys who knew about water, ropes, ladders and didn't freak out at altitude...' "

The villain of the piece is linked effectively into the folklore and old stories, and is suitably chilling, with vivid motivations. His ability to send his spirit into the various citizens of London means that no one can be trusted - and he sends most of his victims to a suitably hideous death. It made me shudder on a couple of occasions.

The only aspect of the novel that was dissatisfactory, truly, was the way Aaronovitch occasionally dumped information in the form of "lessons" - it came thick and fast at some points, and felt a little disjointed.

However, this is minor. Rivers of London is assured, witty and great fun to read. I was incredibly impressed and will definitely picking up the rest of the series.

Rivers of London is published 10th January in the UK by Gollancz.