citizenship without notifying the citizen targeted. This is also a direct response to a case in which a deprivation decision was successfully challenged: in D4, the Supreme Court ruled that it was unlawful to deprive a person of their citizenship without telling them (in the case in question, the notice had literally been put in a drawer). The evolution of the law, mostly in direct response to cases that have not gone the Government’s way, demonstrates that the UK is seeking to entrench the position that "citizenship is a privilege, not a right",20 and to respond to cases where deprivation was not possible due to safeguards in the law. Critics warn that “parliament has given the government unprecedented power to act as judge, jury and executioner without adequate safeguards on the use of that power”.21 If passed, the 2021 Bill would further erode the rule of law and procedural standards, accelerating the UK’s race to the bottom.22 MILITARY SERVICE TO A FOREIGN COUNTRY The second security-related ground of loss is the rendering of military service to a foreign country, which can be found in the legislation of 70 of the 190 countries studied (meaning that a majority of 120 states provide for no such ground for loss). In 53 countries of these 70 countries, the loss provision is generally applicable to all citizens, while in a minority of 17 countries, it is restricted to certain groups of nationals – usually nationals by naturalisation. Provisions of this nature generally refer to formally entering a foreign military and/or taking up a position in a foreign army, although the boundaries may be subject to the interpretation of the authorities. The extent to which military service can result in loss of nationality varies. For example, in a U.S. administrative decision, it was determined that engaging in unarmed weekly military marching was insufficient to result in loss of United States nationality.23 On the contrary, commentaries on the German loss provision consider that affiliation to a foreign army is the determining factor in this regard and that the function of the person concerned is irrelevant, even if the person only provides minor (non-combatant) services. The provisions usually only cover service in the official armed forces of another state. This means that serving in a non-state armed group generally falls outside the scope of these provisions, although the exact interpretation differs from state to state. The Netherlands, for example, interprets the provision in a restrictive manner and excludes all services to non-army or non-state entities (e.g. guerrilla groups or paramilitary groups).24 In contrast, Germany uses a slightly broader interpretation and also covers services to a paramilitary state organisation.25 The provisions are not necessarily restricted to service to the armed forces of a recognised state; in the United States, for example, service to the army of an unrecognised state that engages in hostilities against the United States can also result in the loss of nationality.26 In a majority of the countries, the loss of nationality is subject to additional conditions or safeguards. In 19 countries,27 nationality can only be lost on this ground if a person has not obtained prior permission to enter a foreign military service. In 14 countries,28 nationals only lose their nationality on this ground if they have been ordered to leave foreign military service. Only if the person retains the position after a certain timeframe, can nationality be lost. For example, Chadian nationals by naturalisation can lose nationality if they retain a position in a foreign army for more than six months after they were ordered to resign.29 In nine countries,30 the provision can only be applied to a person who provides military service to an enemy state. In most of these countries, this implies that the other state should be involved in hostilities or warfare against the country. Some states use a lower bar, such as Romania, where the law refers to severed diplomatic relations. In 14 countries,31 the provision only covers voluntary military service. This implies that persons who are obliged by law to perform military service in a foreign country (e.g. dual citizens) will not lose their nationality on this ground. UKRAINE: EUROPE CONFRONTS A NEW ‘FOREIGN FIGHTER’ PHENOMENON On 7 March 2022, Ukraine announced that over 20,000 foreign nationals from 52 countries had expressed their desire to join the Ukrainian armed forces since the country was invaded by Russian military forces two weeks earlier.32 They responded to a call of the Ukrainian president Volodymyr Zelenskiy for foreigners to join the Ukrainian army’s international legion.33 In addition to that, it is likely that numerous Ukrainian dual nationals have joined the Ukrainian military. It is perhaps telling that when making this announcement, Ukraine refused to specify the countries of origin of the combatants, as the issue of foreign fighters is evidently a controversial one. First of all, in some states it is considered an offense for a citizen to join a foreign army. The UK foreign secretary Lizz Truss was criticised for saying that she “absolutely” supported Britons joining the Ukrainian army, even though joining a foreign army not engaged in hostilities against the United Kingdom is a criminal offense under the Foreign Enlistment Act.34 Secondly, as demonstrated in this report, joining a foreign army can put one’s nationality at risk. This poses a problem for countries that have taken a strict stance on the issue of foreign fighters in recent years but now voice support for Ukraine. In some countries (e.g. the Netherlands), nationality is only lost on this ground if a national joins the army of an ‘enemy state’, which could exempt people who join the Ukrainian ranks. If there no such clause, the problem is more difficult to resolve. For example, German-Ukrainian dual nationals who voluntarily joined the Ukrainian army risk losing their German nationality automatically. Hence, it has been reported that the German Federal Ministry of Defense is “examining a solution” for Ukrainian-German combatants.35 Other countries have taken stronger measures. On 28 February 2022, the Latvian parliament adopted an amendment that exempted citizens who joined the Ukrainian army from Art. 24(2) of the Latvian Law on Citizenship, which provides for the loss of Latvian citizenship upon joining the armed forces of a foreign state without prior permission.36 11