SAS trooper Dan "Spider" Shepherd in action in Afghanistan, on the trail of a murderous Taliban assassin.

Shepherd went on to become an undercover cop in London in the series written by bestselling author Stephen Leather.

Kill Zone is just under 14,000 words long, about thirty pages, perfect if you have half an hour to spare.

Stephen Leather is one of the UK's most successful thriller writers. He was a journalist for more than ten years on newspapers such as The Times, the Daily Mail and the South China Morning Post in Hong Kong. Before that, he was employed as a biochemist for ICI, shovelled limestone in a quarry, worked as a baker, a petrol pump attendant, a barman, and worked for the Inland Revenue. He began writing full time in 1992. His bestsellers have been translated into more than ten languages. He has also written for television shows such as London's Burning, The Knock and the BBC's Murder in Mind series. Two of his books, The Stretch and The Bombmaker, were made into movies.