Rooney’s thought-provoking third novel is loosely based on the true story of Melita Norwood, the 87-year-old (nicknamed ‘The Spy who came in from the Co-op’!), arrested in England in 1999 after spying for the Russians for four decades.

Unlike Norwood, protagonist Joan Stanley, was never a committed communist, and the story provides a credible and highly readable account of the complex reasons someone might betray their country. Who can say for sure what they would have done faced within similar moral dilemmas in a time when it looked as though the whole world had gone mad?

The narrative is deftly woven between Joan’s 2005 interrogation by MI5 and her previously suppressed memories of living in Cambridge, first as a science student and later working, ostensibly as a secretary, in an atomic research establishment. Echoing the way Joan was beguiled by Russian-born Leo Galich and his controlling and charismatic cousin Sonya, Rooney skilfully draws the reader in to the intrigue in the run-up to the Second World War and its aftermath, when the University was awash with idealists.

Despite Joan’s love for Leo, it isn’t until the horror of Hiroshima that she gives in to his coercion and begins to pass atomic secrets to Stalinist Russia, in the misguided belief that there is more chance of world peace if the Russians are also in possession of the atomic bomb.

There are a couple of twists in the story which, for discerning readers, are easy to anticipate.  But, the characters are well-developed, fostering a certain sympathy for Joan, despite her reluctance to admit, even to her son, that she may have been wrong.