Prof David Balmforth, a former president of the Institution of Civil Engineers, said that conventional defences, such as the barriers that line the river Greta in Keswick, had to be supplemented with more innovative methods.

We tend to design defences to a particular standard, to give an annual probability against flooding, which might be, say, a one-in-100- or one-in-200-year chance of the defence being overtopped,” he said.

“That would be a typical sort of figure that would be used. The question that now remains is: were the events that we’ve now seen in recent days so excessive that it’s reasonable to expect them to overtop defences?

Suggesting ways of coping with future deluges, Balmforth cited work that was done in Nepal. He said: “They have regulated minimum threshold levels about a metre above surrounding ground for any new major development, whether or not it’s in a flood risk area.”