And it continued as a palace favourite throughout the late Queen Elizabeth II’s reign: she reportedly received boxes of Bournville, the brand’s red-wrappered dark chocolate, every Christmas.

A gooey, fudgy brownie is the ultimate chocolate treat, and Mary Berry has shared her recipe for the ultimate batch - and it's simpler than you might think ...

“Start by mixing 360g of dark chocolate with 225g of butter ... Ingredients 360g (12 1/2 oz) Bournville plain chocolate (2 x 180g packets), broken into pieces 225g (8oz) butter, cubed, plus ...