He has written two books, both of them spy novels, The Riot Act (1997), published by Serpent's Tail, and The Cardamom Club (2003), published by Blackamber (now part of Arcadia Books). The Cardamom Club was published in India (2004) by Penguin Books.

The Riot Act was short-listed by the Crime Writers' Association for its best first novel award. It has been published in France by Éditions Gallimard as Lutte Des Casses (2002) as part of its acclaimed serie noir imprint.

Stock signed a three book deal in July 2008, with Blue Door, a new HarperCollins imprint, for "a good six-figure sum", according to The Bookseller (15/7/08). The first book, a spy novel called Dead Spy Running, was published in July 2009.

Warner Bros. acquired the movie rights to the Dead Spy Running franchise in October 2008 to make the first of a proposed three movie franchise, they signed on Charlie's Angels director McG to direct the movie along with Stephen Gaghan to write the screen play. It was initially reported that after the shooting of McG's last movie Terminator Salvation, he would be taking up the shooting of the remake Captain Nemo: 20,000 Leagues Under the Sea, but with the cancelling of this movie by Disney it appears that Dead Spy Running will be the next movie to be taken up.