Not your usual tea, cakes and the vicar Agatha Christie story - but then not many of them are. She liked to use her experiences travelling in the Middle East and around the world. I can imagine her sitting in a hotel looking around at the other guests: suppose that archetypal Englishwoman was really an agent of MI6? And that plump American lady was in the pay of Them? That shrivelled but distinguished old man - perhaps he is so rich that he really runs the world, or thinks he does. Or would like to. Those tweedy young men claiming to be archaeologists: are they really on the trail of Him? Christie knew a lot of tweedy young archaeologists (she married one) in Iran and Syria in the 30s. Perhaps they were really spies too? This story, like They Came to Baghdad, is reminiscent of John Buchan at his best. The chilling atmosphere of the Unit is brilliantly imagined, and the types, briefly sketched in, who flourish in institutions and love to be part of a System. "Ah, Mr. Bond, come in, I have been expecting you ... " The swivel chair swings round to reveal the mastermind - Agatha Christie!