Ireland and the independence of the Irish Free State in 1922, which left Northern Ireland as the only part of the island of Ireland within the United Kingdom, the name was changed to the "United Kingdom of Great Britain and Northern Ireland". Although the United Kingdom is a sovereign country, England, Scotland, Wales and Northern Ireland are also widely referred to as countries. The UK Prime Minister's website has used the phrase "countries within a country" to describe the United Kingdom. Some statistical summaries, such as those for the twelve NUTS 1 regions of the United Kingdom refer to Scotland, Wales and Northern Ireland as "regions". Northern Ireland is also referred to as a "province". With regard to Northern Ireland, the descriptive name used "can be controversial, with the choice often revealing one's political preferences". The term "Great Britain" conventionally refers to the island of Great Britain, or politically to England, Scotland and Wales in combination. It is sometimes used as a loose synonym for the United Kingdom as a whole. The word England is occasionally used incorrectly to refer to the United Kingdom as a whole, a mistake principally made by people from outside the UK. The term "Britain" is used both as a synonym for Great Britain, and as a synonym for the United Kingdom. Usage is mixed: the UK Government prefers to use the term "UK" rather than "Britain" or "British" on its own website (except when referring to embassies), while acknowledging that both terms refer to the United Kingdom and that elsewhere "British government" is used at least as frequently as "United Kingdom government". The UK Permanent Committee on Geographical Names recognises "United Kingdom", "UK" and "U.K." as shortened and abbreviated geopolitical terms for the United Kingdom of Great Britain and Northern Ireland in its toponymic guidelines; it does not list "Britain" but notes that "it is only the one specific nominal term 'Great Britain' which invariably excludes Northern Ireland". The BBC historically preferred to use "Britain" as shorthand only for Great Britain, though the present style guide does not take a position except that "Great Britain" excludes Northern Ireland. The adjective "British" is commonly used to refer to matters relating to the United Kingdom and is used in law to refer to United Kingdom citizenship and matters to do with nationality. People of the United Kingdom use several different terms to describe their national identity