It may be the great spymaster’s last mystery. Who will break four decades of silence to come forward as John le Carré’s “secret mistress and muse”?

A hitherto unknown author, writing under the pseudonym Suleika Dawson, is to publish a new intimate memoir of the spy novelist called The Secret Heart. It is billed by its publisher as a portrait of le Carré “by the woman he kept secret for almost half his life”.