London Match
by Len Deighton
Samson suspects that there is a traitor within his department of MI6, due to the appearance of a memorandum which was leaked to the KGB. It transpires that it is part of a plot conducted by his wife—now working for East German intelligence—to frame his superior, Bret Rensselaer, as a KGB agent. When Samson's old friend Werner Volkmann is arrested by the East German police Samson organizes an unauthorised exchange of defector Erich Stinnes for him, but the operation ends in a shoot-out on the Berlin [[S-Bahn]].