Outward appearances suggested that Frank Hart and his wife Kathleen, who lived together in Hill View Crescent, Redbridge, were a respectable middle-aged couple. They had an adoring friend, Olive Good, 26, who called on them regularly; apart from her visits the Harts’ lives were suburban and uninspiring.

All that changed in the evening of April 28th, 1937, when Frank Hart suddenly went berserk. He battered his wife and Olive unconscious, turned on the gas oven, and lay down on the floor to die with them.

They died, but Hart didn’t. And when, at his trial on MAY 28th, he insisted on pleading guilty to murder, the judge ordered an investigation into his state of mind. As a result Hart was found insane and sent to Broadmoor.