spy sinker - Len Deighton

The hero of Spy Hook and Spy Line returns for a final bow in Len Deighton's thrilling novel, Spy Sinker. British agent Bernard Samson's family and career are about to be betrayed and crushed by his wife - lovely, brilliant Fiona Samson.
Recruited by the Russians as an Oxford student, Fiona's risen to the rank of colonel in the KGB. She's also the golden girl of British intelligence, their East German superspy. Or is she?
Fiona. Double agent. Traitor and patriot. Wife and mother. Now, she's on a desperate, violent, unparalleled mission of worldwide importance...so important that there is only one way she can succeed: through terrible treachery to the ones she loves most.