2 Melbourne University Law Review [Vol 41(2):Adv 3 Use and Efficacy .................................................................................33 III Themes and Observations..........................................................................................37 IV Conclusion ...................................................................................................................44 I INTRODUCTION In recent years, three common law countries, the UK, Canada and Australia, have enacted legislation to broaden the capacity for nationals to be stripped of their citizenship. This represents a reinvigoration of security-based denationalisation: a practice which has been largely unused for several decades. The laws have been introduced in response to heightened concerns about national security stemming from the foreshadowed return of radicalised ‘foreign fighters’,1 terrorist attacks in Western nations,2 and planned or attempted attacks on home soil.3 The case for introducing new citizenship revocation measures has been made on the basis that additional powers are needed to respond to these challenges. For instance, in a press statement in 2014 announcing that the UK threat level had been raised to ‘severe’, then-Prime Minister David Cameron noted that ‘[t]he ambition to create an extremist caliphate in the heart of Iraq and Syria is a threat to our own security here in the UK’.4 Cameron continued: 1 See, eg, Lydia Khalil and Rodger Shanahan, ‘Foreign Fighters in Syria and Iraq: The Day after’ (Analysis, Lowy Institute for International Policy, September 2016) <http://web.archive.org/web/20160913001824/http://www.lowyinstitute.org/files/khalil_and_ shanahan_foreign_fighters_in_syria_and_iraq_final_web_120916.pdf>. 2 See, eg, Alice Foster, ‘Terror Attacks Timeline: From Paris and Brussels Terror to Most Recent Attacks in Europe’, Express (London, 18 August 2017) <www.express.co.uk/news/world/ 693421/Terror-attacks-timeline-France-Brussels-Europe-ISIS-killings-Germany-datesterrorism>, archived at <https://perma.cc/3JDX-MDGH>. 3 See, eg, Natasha Bita, ‘Sydney Siege Shows How the Screen Door of Citizenship Has Been Left Open to Criminal Elements’, The Australian (Sydney, 20 December 2014) <www.theaustralian. com.au/opinion/sydney-siege-shows-how-the-screen-door-of-citizenship-has-been-leftopen-to-criminal-elements/news-story/929eb385f0325e4aa58b7a3b230d4160>, archived at <https://perma.cc/8ZQN-ZRKQ>; ‘Canada Revokes Citizenship of Toronto 18 Plotter’, HuffPost Canada (Online, 26 September 2015) <www.huffingtonpost.ca/2015/09/26/toronto-18terror-plotter-s-citizenship-revoked-by-federal-government_n_8200768.html>, archived at <https://perma.cc/B95E-MTXA>; Victoria Parsons, ‘Man Stripped of UK Citizenship over Fears of Paris-Style Terror Attack in London’, The Independent (London, 26 May 2016) <www.independent.co.uk/news/uk/crime/man-stripped-of-uk-citizenship-over-fears-ofparis-style-terror-attack-in-london-a7048986.html>, archived at <https://perma.cc/QUA3UXFP>. 4 David Cameron, ‘Threat Level from International Terrorism Raised: PM Press Statement’ (Speech, Prime Minister’s Office, 29 August 2014) <www.gov.uk/government/speeches/threat- Advance Copy