If the Duke would not sell voluntarily, he would be made to sell under duress. The mechanism was the Mischief Act — a bill so threatening that accepting £70,000 would seem the better option. The Duke could accept the money or watch Parliament strip everything the revenue had been worth.

Counsel was heard at the Bar of the House. Mr Cooper delivered the most comprehensive constitutional defence of the island’s sovereignty ever heard in a British parliament — and the last. The island was not part of England. It never had been. Parliament’s writs had never run there. Cooper invoked Locke, Grotius, and Pufendorff. He identified the East India Company as the true beneficiary. He asked the House to restrain itself.

Parliament listened. Parliament voted. The Isle of Man Purchase Act, the Mischief Act, and the Smuggling Act passed in the same session as the Stamp Act 1765 — the measure that provoked revolution in America. The Purchase Act destroyed Manx sovereignty just as completely, but without the revolution.

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