A touch of paganism in the boudoir: an ornate gallery designed by Thomas Pitt between 1759 and 1762 at Strawberry Hill

At the end of 1764 literature’s first horror story, The Castle of Otranto, was published in London under disguise. It was an immediate success, despite its fatuousness, and has never since been out of print. It didn’t take long before its author was obliged bashfully to step forward: Horace Walpole, man of fashion, antiquarian, member of the House of Commons, unwavering bachelor and youngest of the five children of Sir Robert Walpole.

Otranto established a genre, the gothic novel, but Horace Walpole had long been delving into spiky realms. In 1747 he had acquired a property outside London overlooking the Thames at Twickenham, a spot already renowned for Pope’s villa. Walpole proceeded to turn a plain little house into a glamorous sham castle, pretty vaults within, battlements without. He