Many things are now normal that would have seemed unlikely a year ago. But even in this strange new world the sudden rise of the sea shanty is, perhaps, strangest of all.

It all started in December when Nathan Evans, a postman from North Lanarkshire, posted a video of himself online — a lone figure filmed in no-frills close-up, hoodie high under the chin, beanie pulled down to the eyes — singing the 19th-century whaling song ‘Wellerman’.