As international law, and in particular human rights law has evolved, a number of key principles have been recognised as limiting state discretion in setting rules and criteria in relation to citizenship. Hence, the UK can set the rules for deprivation of citizenship, but international law limits the UK’s powers in this regard. There is a wide range of well-established and developing international law standards, which states are obliged to uphold when considering the introduction of new powers or the implementation of existing powers to deprive nationality of their citizens. These have been brought together in the Principles on Deprivation of Nationality as a National Security Measure customary international law, general principles of law, judicial decisions and legal scholarship. The Principles apply to any situation in which loss, withdrawal or denial of nationality was not voluntarily requested by the individual. They were developed over a and statelessness, counter-terrorism, refugee protection, child rights, migration and other related areas. TIMELINE NATIONALITY DEPRIVATION POWERS IN THE UK: SECTION 40 OF THE BRITISH NATIONALITY ACT 1981 (AS AMENDED): (2) The Secretary of State may by order deprive a person of a 1948: Nationality deprivation powers narrowed 1973: Last known use of nationality deprivation in 20th century 2004: Suspensive right of appeal removed 2006: Threshold for deprivation is conducive to the public good. (4) The Secretary of State may not make an order under subsection (4A) But that does not prevent the Secretary of State from making an order under subsection (2) to deprive a person of a citizenship status if— (a) the citizenship status results from the person’s naturalisation, public good’ to the public good because the person, while having that citizenship status, has conducted him or herself in a manner which is seriously prejudicial to the vital interests of the United Kingdom, any of the Islands, or any British overseas territory, and 2014: (c) the Secretary of State has reasonable grounds for believing that the person is able, under the law of a country or territory outside the United Kingdom, to become a national of such a country or territory. Power to deprive naturalised British citizens even if they would be made stateless prejudicial to the vital interests of the UK’ 2017: Peak in cases of nationality deprivation BASIC RULE FROM THE PRINCIPLES ON DEPRIVATION OF NATIONALITY AS A NATIONAL SECURITY MEASURE 4.1. States shall not deprive persons of nationality for the purpose of safeguarding national security. 4.2. Where a State, in exception to this basic rule, provides for the deprivation of nationality for the purpose of safeguarding national security, the exercise of this exception should be interpreted and applied narrowly, only in situations in which it has been determined by a lawful conviction that meets international fair trial standards, that the person has conducted themselves in a manner seriously prejudicial to the vital interests of the state. 4.3. The exercise of this narrow exception to deprive a person of nationality is further limited by other standards of international law. Such limitations include: 4.3.1. The avoidance of statelessness; 4.3.2. The prohibition of discrimination; 4.3.3. The prohibition of arbitrary deprivation of nationality; 4.3.4. The right to a fair trial, remedy and reparation; and 4.3.5. Other obligations and standards set forth in international human rights law, international humanitarian law and international refugee law. 4.4. This basic rule also applies to the deprivation of nationality for other purposes, which serve as proxies to the purpose of safeguarding national security, as well proxy measures, which do not amount to deprivation of nationality but are likely to have a similarly adverse impact on individual rights.