Owing to a rise in temperature in southern Europe and a reduction in rainfall, the production of olive oil this year may drop by nearly 40 per cent. For the Romans, who ensured that the olive spread all around the Mediterranean, it would have been disastrous.

Olives were a food, and in its liquid form as oil it was used to light lamps, form a base for medicines and cosmetics, and as a skin moisturiser, cleansing agent, lubricant and contraceptive (Marie Stopes used it in trials and found it 100 per cent successful, whether virgin or extra virgin is not recorded)....