He did, and he didn’t. That is Laura Thompson’s artful conclusion to the enduring question of whether John Bingham, the seventh Earl of Lucan, killed his children’s nanny in his family house in Belgravia forty years ago. She is smart enough to realise the difficulties in arriving at a definitive verdict on the events of that fateful night in November 1974, which policemen, investigators and journalists have pored over for so long. 

On offer (with some variations) are two main versions of the ‘truth’ – Lucan’s and the legal system’s. According to Lucan, he happened to be passing the house when he saw someone assaulting his estranged wife, Veronica. He rushed in but, in an effort to help her, he accidentally killed