And there are pockets where a butty is an open sandwich. This is fine for jam butties (carved door-step-style from an unsliced loaf, tons of butter and a minimum of 1" of jam, which must include as many stawberries as you can dig out of the jar before your mother sees you), but a little unsatisfactory for chips, where you really need the top slice to prevent filling loss (from the sandwich, not your teeth!)

But then most of us have more sense than to put our sarnies in our pockets ...

Steve