IN 1846 A respectable couple moved into a riverside cottage on the Thames at Chelsea. Mrs Booth was in her late forties; her other half – dubbed “Admiral Booth” by the local tradespeople – was 20 years older. The couple had a deck installed on the cottage roof, from which the admiral watched the sun rise and set over the river, and they lived there quietly with almost no visitors apart from the doctor who came more frequently as Mr Booth’s health declined. From October 1851, he was confined to bed, and it was not until the undertakers arrived to take his body to the West End – and thence to St Paul’s – that it emerged that the reclusive admiral was the famous painter J.M.W. Turner (1775-1851). If the news astounded his Chelsea neighbours, it