“It was a devastating night,” says Sheffield historian Ron Clayton.

“Foaming water pounded down Loxley Valley like a train, and everything in its path went down.

“People caught in the middle of it thought the world was ending.”

The Great Sheffield Flood of 1864 killed at least 240 people and destroyed more than 600 houses, when the newly-built Dale Dyke Dam collapsed as it was being filled for the first time, sending three million cubic metres of water smashing through the city, as it slept.

Here, Ron explores exactly what happened on that fateful night, just before midnight on March 11 1864.