Today we regard the oyster and lobster as luxury foods, but it has not always been so. Oysters have been commercially farmed since the time of the Romans and have a remarkable talent: when collected, they close their watertight shells, trapping seawater inside. This useful skill doubtless evolved so they could survive being beached at low tide. But it meant that oysters could be shovelled into a barrel, carted to a city, and left under a bar — sometimes for weeks — while remaining alive and fresh.

Lobsters, or similar forms of invertebrate, crustacean arthropod have been around longer than humans and it is quite possible that we have been eating them for a very long time. They are also unique among the food we eat today in that we often buy them alive and kill them ourselves. They are plentiful, at no particular risk of extinction, and utterly delicious, having sweeter and better-textured flesh than fish. They survive in a wide range of sea temperatures and are easiest caught by simple and sustainable methods.

Like oysters, the creatures’ ability to survive out of water meant they could be transported far inland and supply spankingly fresh protein long before refrigeration made it possible to distribute other forms of fresh fish. For this reason, lobster and oysters were often considered a food of the poor in industrialised cities. Nineteenth-century prison governors in some coastal states of the US were forbidden to feed their prisoners lobster more than a few times a week, as it was considered a “cruel and unusual” privation.