I’m generally speaking not a big fan of writers utilising successful, well-established, ideas and conceits as their central Big Idea for novels. On the face of it, that’s what Unlundun is: China’s version of Neverwhere. Albeit aimed at a younger audience.

And a cursory flick through the book reveals a somewhat unsurprising thank you/acknowledgement of Neil’s contribution to “London phantasmagoria” (fab word: phantasmagoria, and one you so rarely get an opportunity to use). Now I’m fairly certain from what’s been said by Neil in the past that he has no problem with this and indeed this review is not going to debate the merits of this approach.

The point is I was going to be a hard sell for this book.

Unlundun is the flip side of London, the place where all the things that fall through the cracks of the city wind up and where war is brewing. Zanna and Deeba are two friends who begin to notice that strange things are happening to Zanna. Approached in the street by strange people, things are being written in the sky about her and animals are paying her the most curious attention.

Following an errant umbrella they find themselves in a new place, a different London, an Unlundun. A strange place haunted by feral giraffes, conductors who actually conduct electricity, words come alive and where an evil cloud plans to take over the city. And where Zanna is hailed as a prophetic hero. Much to Deeba’s annoyance.

This is China’s first foray into children’s literature and it does show. Children’s literature works best when the author doesn’t talk down to the reader, and although the book is unflinchingly smart – as you’d expect from China, there are places where his voice becomes a touch patronising. I’m thinking mainly of the opening chapters where the primary hook is also a little weak although I particularly enjoyed the friendly pop at the genre.

Really once that gag, or conceit, whatever you want to call it, is out of the bag and in the open then it becomes a much more fun book to explore. There is a frenetic pace of invention, cleverness and joy in the written word that bleeds out of each page hopefully infecting the target audience.

As someone who spent ten years in London as child, there was something deeply familiar about Unlundun and that artful capturing – or possible remembering – of childhood in the city is a mark of fantasy at it’s best. Too often we see a romanticised view of childhood: in the country, in boarding schools and city kids are often looked on with a kind of pity. Forgotten or overlooked is the sheer imaginative inventiveness of children in turning the detritus of the city into entire worlds, where a piece of rubbish can be transformed into a pet or an umbrella into a weapon.

It’s great to see someone taking that dark, dirty, urban sprawl and turning it on its head, showing the magical side of the city.

Unlundun is by no means a perfect book: the beginning of the book clunks a little, there are one or two characters – such as Zanna – who are not fleshed out enough and the close proximity to Neverwhere might put some off. Yet it’s also smart, fascinating, enthralling, funny and wonderfully inventive. A book that as a boy I would have loved to have up on my shelf, that would have had me searching for more books in the same ways as the works of Dahl, Lewis and Tolkein did.

And ultimately that’s the point of a good children’s book.