Spy hook. Len Deighton. 1989.

Working for the Department was like marriage is supposed to be - “til death do us part” - and so when Bernard Sanson’s wife Fiona, defected three years ago it was a double betrayal and a rejection on several levels. Since then things have not gone well for Samson: old pals are not as friendly as they used to be and colleagues are less confiding than they once were. Now, after his trip to Washington, life has become even more precarious for Bernard. Ignoring all warnings, friendly and otherwise, he pursues his own investigation into Fiona’s defection and, in California, meets with the biggest surprise of his life...