Besides the good story, well told, this book is a masterclass in how to structure and pace a novel. The author clearly knows how to edit, as this is just the right length. So many books start well, but outstay their welcome. It is a cracking good read.

The story is familiar to anyone who enjoys dystopian speculative fiction (Atwood et al.). It echoes the recent BBC Radio 4 play 'Borderland' (www.bbc.co.uk/programmes/b08dnhjx), with themes of migration and what happens when nationalism and nativism lead governments into unravelling the social contract. One of the points of the book is that if we allow our government to treat 'the Others' as undesirables without rights, then in so doing we enable a process whereby our own rights are discarded. The distinction between us (with comfort and prosperity) and the others (facing insecurity and death) becomes a bureaucratic distinction. Too easily, we can find ourselves on the wrong side of The Wall.

The book appears to be about climate change, and inter-generational strife, but these themes are, I think, incidental to the plot. Which I hope allows for the possibility of a sequel that digs into those issues more thoroughly.