The Monday morning Julien Freret will never forget began at 5am on 12 October with an unexpected phone call from a baker. “I think you need to come,” the baker said. “There’s a big, big, big problem with the refrigeration.”

By the time Freret arrived at the Intermarché supermarket he had managed for two years in the historic town of La Haye in Normandy, France, the fridges had reached temperatures of around 50°C. And they were still rising.

“That was when panic set in,” Freret recounted to Business Insider. “We thought: this can’t be possible.”