Unsuccessful Booker nominee finds its way swiftly to paperback, and we the public are again asking just what it is about that particular prize that brings out the bizarre in its judges.

Not that The Underground Man is a bad book. Film-maker Mick Jackson can clearly write and knows how to throw a workable plot together. This one is about the fifth Duke of Portland, a genial but cracked Victorian aristo who spends his days conceiving a network of carriage-wide tunnels to run beneath his sprawling Nottinghamshire estate. They take five years and hundreds of labourers to complete. And when they are, well...well, what?

Part of the problem with The Underground Man is that Jackson has latched onto an admittedly striking image in this subterranean infrastructure, but, once the book has a title, he all but abandons it. Instead there's a disjointed journey into the escalating mania that swarms inside the master's skull. He toys with increasingly outlandish ideas, sees a ghostly boy hovering in the air beside him, and ultimately takes an unhealthy interest in trepanning.

Jackson resolutely fails to engage emotionally or intellectually with this "whimsical old fool," leaving us as passive observers to his encroaching madness. And who fails to see its revelations a long way off the end? As fictional madness goes it lacks both the Gothic authority of Patrick McGrath's unreliable narrators and the genuinely wacky surreal of Viv Stanshall's Sir Henry At Rawlinson End.

It's a first novel that leaves plenty leeway for the future, but offering him as a sacrifice to the gods of Booker through this entirely competent but utterly unexceptional book does Jackson no favours.