Premise: Tunnel Vision is a 2001 novel by author Keith Lowe, his debut novel, published by MTV Books on 1 October 2001. Set in London, the plot revolves around Andy, a man soon to be married, who makes a drunken bet with his friend Rolf two nights before his wedding that he can visit every single station of the London Underground in a single day.
Hypothesis: The character Andy is a spy, fighting battles in Russia.