Number 50 Berkeley Square in Mayfair has held the reputation of London's most haunted house since the Victorian era. The four-story Georgian townhouse, now occupied by the antiquarian bookseller Maggs Bros., was the subject of terrified speculation throughout the 19th century, and the nature of its haunting remains one of the great unsolved mysteries of British ghost lore — because unlike most haunted houses, no one has ever been able to identify what, exactly, haunts it.
The stories began in the 1840s and escalated throughout the century. The entity in the top-floor room was described not as a conventional ghost but as something far more disturbing — a shapeless, suffocating presence that drove witnesses to madness or death. In one widely reported incident, a maid who slept in the attic room was found the next morning standing rigid in the center of the room, her face contorted in an expression of absolute terror. She never recovered her sanity. In another account, a young man accepted a bet to spend the night in the room. He was given a bell to ring if he became frightened. The bell rang once, briefly, in the small hours. When his friends rushed upstairs, they found him dead on the floor, his face frozen in a rictus of horror.
Two sailors who broke into the empty house in the 1870s reportedly slept in the attic room. One fled screaming into the street; the other was found dead, impaled on the area railings below, having apparently thrown himself from the window to escape whatever he encountered. The house became so notorious that it was reportedly investigated by police, and the top floor was left permanently sealed. The current occupants maintain that the building is entirely ordinary, but 50 Berkeley Square's place in the canon of London's supernatural history is secure.