In Emil Zola’s novel La b?te humaine trainspotters see a murder being committed on a train as it flashes by. In Leeds, Yorkshire, on Thursday, February 22nd, 1968, the reverse happened – passengers on the 8.37 p.m. from Hull saw a woman being murdered on waste land as the train rattled past the parish church at Kirkgate, near Leeds, at 10.18 p.m.

She was Mary Judge, 40, well known in the area around Kirkgate because she liked a drink and was forever cheerful. Her battered and almost naked body was found at midnight by a passer-by – her clothes were scattered about.

A small boy on the train, which passed within 50 yards of the murder scene, was the main witness. He saw a tall, slim man with long dark hair beating Mary to the ground. Despite the blood that would have spattered his clothes, he was never found.