On January 24, 1941, the body of Josslyn Hay, Earl of Erroll was found lying on the floor of his Buick outside Nairobi – with a bullet in his head. Erroll, at 39, was influential in the Kenyan Happy Valley community, charming, good at bridge and polo and devoted to the seduction of other men’s wives – preferably rich ones.  Incredibly ruthless in his hedonistic pursuit of pleasure, he had wrecked many marriages.  Sir Henry ‘Jock’ Delves Broughton, whose wife Diana was Erroll’s current conquest, had the most obvious motive.  He stood trial with implacable calm, was acquitted and emerged unscathed.  No-one was ever convicted for the murder and the case has become a classic mystery as well as the scandal  that exposed the extravagant, sybaritic way of life of the enchanted feudal paradise known since the 1920s as Happy Valley, the community of English aristocrats who subscribed to the three As: altitude, alcohol  and adultery.