Some manufacturers buy in ready-made heel lifts, as this is a process that lends itself to mass-production. Loake, as it happens, make their own. The heel is a stack of several layers of hard, vegetable-tanned leather – often with a rubber heel-tip or complete layer. Metal slugs (nails to you and me) are driven through the layers of the heel to give it strength.
Sometimes you’ll see a corner cut off the inside of each heel on a pair of shoes – this is known as a gentleman’s notch or gentleman’s corner. It was first used to prevent the wearer’s heel from getting caught on the turn-ups (or “cuffs” in the USA) of your trousers. Nowadays, they are largely a sign of a well-made pair of shoes and a nice example of the attention to detail that is characteristic of a good shoemaker.