Indefinite leave to remain (ILR) is an immigration status granted to a person who does not hold right of abode

Right of Abode (United Kingdom)

The right of abode is a status under United Kingdom immigration law that gives an unrestricted right to live in the United Kingdom. It was introduced by the Immigration Act 1971.-British citizens:...

 in the United Kingdom

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 (UK), but who has been admitted to the UK without any time limit on his or her stay and who is free to take up employment

Employment

Employment is a contract between two parties, one being the employer and the other being the employee. An employee may be defined as:- Employee :...

 or study, without restriction. When indefinite leave is granted to persons outside the United Kingdom it is known as indefinite leave to enter (ILE).

A person who has indefinite leave to remain, the right of abode

Right of abode

The right of abode is an individual's freedom from immigration control in a particular country. A person who has the right of abode in a country does not need permission from the government to enter the country and can live and work there without restriction....

, or is an Irish

Republic of Ireland

Ireland , described as the Republic of Ireland , is a sovereign state in Europe occupying approximately five-sixths of the island of the same name. Its capital is Dublin. Ireland, which had a population of 4.58 million in 2011, is a constitutional republic governed as a parliamentary democracy,...

 citizen, has settled status if resident in the United Kingdom (all British citizens have the right of abode).

Settled status is central to British nationality law

British nationality law

British nationality law is the law of the United Kingdom that concerns citizenship and other categories of British nationality. The law is complex because of the United Kingdom's former status as an imperial power.-History:...

, as the most usual route to naturalisation or registration as a British citizen requires that the applicant be settled in the UK.