Channel Island which appears in Manx constitutional and administrative sources as a frequent comparator for the Isle of Man.

When the Duke of Atholl discussed proposals for the Crown to acquire Mann in the eighteenth century, he argued that transfer of the lordship would not remove the Island's separate laws and internal government. In a memorandum copied in 1759 he compared Mann directly with “Guernsey Jersey Sark and Alderney”, where imports and exports were governed by their own laws despite their allegiance to the same Crown.

Guernsey and Mann also appear together in Commonwealth administrative records. After the Civil Wars, the Council of State dealt separately with the surrender, garrisoning and government of several island jurisdictions. A 1655 list of English and island garrisons included Guernsey, Jersey and the Isle of Man among the places whose military establishments were being reviewed.

The comparison was therefore practical as well as constitutional: all were island jurisdictions under the English Crown whose local government, defence and customs arrangements required separate administrative treatment.