A fascinating letter from Albert Einstein has surfaced 92 years after he described enjoying the “enviable solitude” of Norfolk while hiding from the Nazis.

The legendary scientist fled to Belgium after Hitler’s rise, but still faced threats. Police protection wasn’t enough, so he crossed to Dover and was driven to a tiny 9m² hut on Roughton Heath, near Cromer, hosted by Conservative MP Oliver Locker-Lampson.

Despite the Spartan conditions, Einstein told his son Eduard he was relishing the peace, spending most of his time doing maths and running outside when cold.

Starting the letter dated September 23, 1933, from Cromer, he confided: “Times have been rather turbulent… It was actually reported… plans for my assassination… My little house… consists of a single room… Outside the door you have immediate access to Mother Nature.”

He called the Nazi takeover of his homeland Germany, “a revolution of the stupid against the rational” and received visitors like sculptor Jacob Epstein, who made a bust of him.

Einstein left England for the US in October 1933, never returning to Europe before his death in 1955.

The two-page letter, kept in the Einstein family until 2001, is now up for auction at Christie’s London, estimated at £20,000-£25,000.

Thomas Venning, Christie’s books specialist, said: “It shows Einstein’s humour amid stress. Despite threats, he joked about getting peace and quiet when dead but not enjoying it. His line about Nazism as a ‘revolution of the stupid against the rational’ was a powerful critique. His love of solitude and nature shines through.”

Venning added the irony of the world-famous genius hiding in a Norfolk hut, guarded by locals with shotguns, was “Dad’s Army-like” and that the British press’s coverage lessened the secrecy of his refuge.

The sale takes place on July 9.