The ‘duck and cover’ drills of 1950s America are infamous — mostly because the idea of a flip-top desk acting as some sort of impenetrable shield while the rest of the school is wiped out in a fiery mushroom cloud is pretty ridiculous.

But as it turns out, the sweet and slightly terrified-looking schoolchildren in those grainy photos, with their Brylcreem and bows, weren’t hiding from the A-bomb at all, but the adult brandishing a tattoo gun.