King of the Ants by Charlie Higson
It seemed straightforward enough. Sean had now consumed so much alcohol that everything seemed perfectly reasonable. He'd started planning the job already. The first problem was how to do it. Thirteen thousand pounds in an envelope seems a fair price for a man's life. Particularly if you don't know the man, he seems a nonentity, and you quite fancy his wife. And there's no chance of being caught. Sean is a drifter, working as a building labourer and waiting for something to happen. When Sean is offered easy money to tail someone and even more easy money to dispose of him, it's all more tempting than you might think. Except when you realize that you've been led up the garden path the whole way...KING OF THE ANTS is dark, disturbing and violently comic. In the tradition of both Joe Orton and Iain Banks, Charles Higson pinpoints the casual vagaries of evil and its attendant powers. Unnerving, horribly accurate and wickedly enjoyable, it remains Higson's finest book.