French novelist Emile Zola wrote a bestseller, La B?te Humaine, towards the end of the 19th century about a man who saw a murder happening in a train compartment as the train flashed past him. A few years later, on Friday, September 22nd, 1905, a signalman at Purley Oaks, Surrey, on the London to Brighton line said he saw the same thing – a couple struggling in a carriage as a train flashed by.

Four hours after that the severely mutilated body of teenager Mary Sophia Money, a dairymaid, was found in Merstham Tunnel, halfway down the line.

The police speculated that she had met a man who lured her on to the train at Victoria either to go for a ride or to see her home to Clapham, the first stop. He then pushed her off the train in the tunnel.