The Bailiwick of Guernsey is a separate jurisdiction in itself, and is in turn also three separate sub-jurisdictions. It does not form part of, and is separate from (but is not independent of, or from) the United Kingdom.[12] The two Bailiwicks of Jersey and Guernsey together make up the Channel Islands.
The Islanders have never had formal representation in the House of Commons of the British Parliament,[8] nor in the European Parliament.[12] Those Islanders who were not somehow qualified and eligible in their own right to register to vote and to vote in the United Kingdom under the Representation of the People Acts as overseas voters, were excluded from the 2016 United Kingdom European Union membership referendum.
Guernsey has an unwritten constitution arising from the Treaty of Paris (1259). When Henry III and the King of France came to terms over the Duchy of Normandy, the Norman mainland fell under the suzerainty of the King of France. The Channel Islands however remained loyal to the British crown due to the loyalties of its Seigneurs. But they were never absorbed into the Kingdom of England by any Act of Union and exist as "peculiars of the Crown".
A unique constitutional position has arisen as successive British monarchs have confirmed the liberties and privileges of the Bailiwick, often referring to the so-called Constitutions of King John, a legendary document supposed to have been granted by King John in the aftermath of 1204. Governments of the Bailiwick have generally tried to avoid testing the limits of the unwritten constitution by avoiding conflict with British governments.
This peculiar political position has often been to the benefit of islanders. Until the 19th century, the Bailiwick was generally able to be exempt from the harsher parts of Westminster legislation, while being included in favourable policies, such as protectionist economic policies. England, and later the United Kingdom, passively exploited the strategic benefits of the Channel Islands. For example, they were able to serve as a convenient stop-off point for trade to Gascony.[13]