Few jars of brown goo summon such associations of comfort and cosiness as Branston Pickle. Its glistening lumps are as nostalgically British as crisps and pork pies, the stuff of ploughman’s lunches in smoky pubs and toasted sandwiches on Sunday afternoons.

Expatriates in lockdown have been shipping it out in bulk to keep homesickness at bay, along with Jaffa Cakes, crumpets and Cadbury’s Creme Eggs. But how many people who spread Branston on their stilton know that, commercially speaking, it is no more British than sushi and saké? None at all knows the agonising family battle that lies behind the familiar brand, a drama played out in courtrooms in Tokyo and London.