2017] Citizenship Stripping Laws in the UK, Canada and Australia 13 question of what the revocation expansions would add to such laws.50 The following section outlines the way in which the UK’s citizenship revocation powers have been used in the 21st century, examines their overlap and interaction with other security-based legislation, and analyses their utility as a means of serving the justifications supplied for them. 3 Use and Efficacy The three 21st-century expansions of UK denationalisation powers have been characterised by ever-broadening executive discretion and limited safeguards. As noted above, a key justification for this was that each set of expansions was a necessary update that would serve to make UK law better adapted to meet contemporary challenges. Despite this, for several years the expanded laws did not see significant use, but rather were invoked only sparingly. Moreover, where revocation powers were invoked, they did not necessarily provide targeted and effective responses to security challenges. This is demonstrated by the only attempt to invoke the power granted to the Home Secretary in 2002 to revoke a person’s citizenship where the Secretary reasonably believed that they had conducted themselves in a manner seriously prejudicial to the vital interests of the UK. Three days after this revocation power entered into force, it was used to revoke the citizenship of Abu Hamza al-Masri,51 a radical cleric who had publicly praised the September 11 terrorist attacks and Osama bin Laden.52 At this time, Abu Hamza was a dual citizen of the UK and Egypt, and therefore susceptible to denationalisation. The legislation at the time, however, provided that deprivation did not come into effect until a person had exhausted all of their appeal avenues. Abu Hamza lodged an 50 A criticism of the 2002 law was that most conduct seriously prejudicial to the vital interests of the UK was already criminalised and penalised through treason offences. The government’s response was that it wanted to retain the power to revoke citizenship even where a criminal conviction was not or could not be secured; for instance, due to a lack of sufficient admissible evidence: see, eg, United Kingdom, Parliamentary Debates, House of Lords, 9 October 2002, vol 639, cols 279–81 (Lord Filkin). 51 Hamza v Secretary of State for the Home Department (Special Immigration Appeals Commission, Appeal No SC/23/2003, Mr Justice Mitting (Chairman), Senior Immigration Judge Goldstein and Mr Smith, 5 November 2010) [2]. 52 Lena Jakobsson, ‘Jury Finds Radical Islamic Cleric Abu Hamza al-Masri Guilty in Terror Trial’, CNN (Online, 20 May 2014) <http://edition.cnn.com/2014/05/19/justice/new-york-terrortrial/index.html>, archived at <http://perma.cc/7ZBN-FFYD>. Advance Copy