“Have a glass of whisky on us,” a stranger and his male companion said to Fleetwood Willats, a 72-year-old widower, in a Tottenham, north London, pub. Fleetwood nodded his appreciation. He normally drank beer, but a whisky was always welcome.

He took two sips from the glass and then pushed it away. “It tasted like sweet wine, and burned my mouth,” he said later. Next day, Friday, June 13th, 1919, he was taken ill and died in hospital that evening. Cruelly, he had been given hydrochloric acid.

He was unable to describe the two men in the pub and no other cases like it were ever reported.