London Stone was embedded in the wall of St. Swithin's Church on Cannon Street, where it had been since at least the 12th century. The traditional belief held that it was the milliarium — the central stone from which Roman Britain measured all distances, equivalent to the Golden Milestone in Rome. Later tradition associated it with Brutus of Troy, the legendary founder of Britain: it was supposedly the altar stone he brought from Troy when he founded Troia Nova (the original name for London). Geoffrey of Monmouth and later chroniclers claimed that 'so long as the Stone of Brutus is safe, so long shall London flourish.' For Cade to strike it is to perform the founding gesture of sovereignty itself — claiming the stone is claiming everything the stone represents. That he follows this with a decree about a small urinating conduit is the joke.

Cade's final command — burn London Bridge, burn the Tower — is the logical endpoint of his political program, which was always destruction rather than governance. From the beginning he has been better at demolishing things than building them: kill lawyers, burn records, abolish money. Now in power for approximately eight lines, his first governing acts are an execution (for a name) and arson orders. The wine-from-the-conduit decree is the one positive promise, and it's absurdist fantasy. Shakespeare is showing us what happens when resentment gets power: it reproduces the violence it claimed to oppose, immediately and without reflection. Cade didn't want to rule; he wanted to smash. Ruling requires the very systems he has declared his enemies.