Ship’s biscuit — baked four times until it had the density of granite ballast — was meant to last for years at sea. In practice, after three weeks in a humid wooden bilge, it became an active biological metropolis.

Old tars knew the customary method: tap the biscuit against the wooden mess table to shake out the white maggot larvae before taking a bite in the dark. But in April 1797 at Spithead, the Channel Fleet put its collective foot down.

The mutiny was remarkably polite. The sailors locked their officers in wardrooms, served them dinner, saluted them punctually, and refused to sail until their purser rations were audited and pay increased.

The Admiralty caved within weeks, and King George III signed a full royal pardon.