It only took me a few hours to read and, at first, I thought it was okay but nothing special. I agreed about it being Garner/Wynne Jones territory - lots of echoes of Elidor and Fire and Hemlock in the mean streets of Magwhite and the scary way that things start to glow around Josh, the eldest of the three protagonists. Then, about halfway through, I realised that I wasn't being disappointed any more, but had been drawn into the story completely, convinced by the way that Hardinge tackles the children's response to the disintegration of their already shaky world. Because, of course, they are all outsiders: Josh could be popular at school but doesn't choose to be, Ryan is small and speccy and worried, Chelle can't stop talking although no-one listens to her; she's pale and asthmatic and sort of just tags along with the others. They are all drawn to Magwhite precisely because they shouldn't be there and when they don't have any money to pay for the bus home, they know that there will be serious trouble. Which they need to avoid: Chelle doesn't know how to deal with being in trouble, Ryan doesn't want to provoke any more family rows, and Josh will be exiled to his aunts' house where he won't be allowed out. So they steal the money from a long-neglected well. And suddenly it's not just everyday trouble they have to contend with, because they are all changed, in frightening ways.
This book is aimed, I think, at a slightly younger audience than Fly By Night, but it doesn't pull its punches. Hardinge knows that there's a lot going on in children's heads that adults don't realise, and some of it's because they don't have the experience to make sense of the adult world, even when to the grown-ups they look bright and manipulative and sometimes just plain bad. By the end of the story, it's all pain and rain and urgency - in 2007, when it was published, there were massive floods in England that summer and it must have seemed prophetic, with its images of rising waters.
The UK edition (it was published in the US as Well Witched) is a thing of great beauty. The picture here really doesn't do it justice, I think it's one of the loveliest book jackets I've ever seen. The back is as lovely as the front. I'd have included it here, but it's too dark to scan easily - what you can't see is that it really looks like tarnished copper. I'm tempted to take it off the book and put it on my wall.
To sum up, Verdigris Deep lacks the wondrous inventiveness of Hardinge's first book, but it's still a well-told story, atmospheric and exciting, firmly-rooted in a nice urban grittiness, and a classy example of the genre. I recommend it.