The Act gave effect to an earlier contract between Charlotte, Duchess of Atholl, and the government of the Kingdom of Great Britain, represented by HM Treasury, to sell the Atholls' feudal rights over the Island to the Crown for a sum of £70,000.

The Act did not go as far as had been proposed: for a period there had been plans to merge the Isle of Man into the English county of Cumberland.

This had met with fierce resistance from the inhabitants, led by the then Speaker of the House of Keys, Sir George Moore.

[2] Under the Isle of Man Purchase Act, the Atholls still retained their manorial rights, the patronage of the bishopric, and certain other perquisites.

[4] This was accomplished by a further Act of Parliament "An Act to empower the Commissioners of His Majesty's Treasury to purchase a certain Annuity in respect of Duties and Customs levied in the Isle of Man, and any reserved sovereign rights in the said Island belonging to John Duke of Atholl" (6 Geo.