21. Under Section 40 of the British Nationality Act 1981 (‘BNA’), the Home Secretary (‘HS’) has the power to deprive a person of their British nationality where the HS ‘is satisfied that deprivation is conducive to the public good’.36 ‘Conduciveness to the public good’ is defined by reference to ‘involvement in terrorism, espionage, serious organised crime, war crimes or unacceptable behaviours’.37 However, the law itself remains vague, and phrases in the guidance such as ‘unacceptable behaviours’ are also vague. 22. Although the Home Office has made statements that it deprives people of nationality only ‘sparingly’,38 no such restriction is built into the legislation, and statistics previously published by the Home Office point in a different direction. 23. There has been a large increase in the UK government's use of nationality deprivation powers in the 21st century. Between 1973 and 2006, it appears no one was stripped of their nationality.39 In the ten years between 2006 and 2015, 36 people were deprived of their nationality on grounds that it was ‘conducive to the public good’.40 In the five years between 2016 and 2020, this surged to 176 people – with 104 people deprived in 2017 alone.41 24. The figures for 2019 and 2020 were not released until March 2022, after several freedom of information requests by RSI were refused. We are concerned that the lack of timely disclosure has limited proper assessment and oversight by civil society, parliamentarians and the public. This exacerbates prexisting concerns regarding the lack of safeguards. Historical development of the law 25. The history of the UK’s nationality-stripping powers raises serious concerns about the possible arbitrariness of the government’s current powers. In the last 20 years, the UK has expanded its nationality-stripping powers mainly in direct response to large-scale violent attacks, including 9/11 and the 2005 London bombings, or high-profile litigation against terrorism suspects – including cases in which the courts found that the Home Office acted unlawfully. 36 The HS also has the power under Section 40 (3) BNA to deprive a person who acquired their British citizenship by registration or naturalisation if they did so by fraud, false representation, or concealment of a material fact. Available at: https://www.legislation.gov.uk/ukpga/1981/61/pdfs/ukpga_19810061_en.pdf. 37See https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/631643/deprivation-nullityChapter-55.pdf. 38 Nationality and Borders Bill: Deprivation of citizenship factsheet’ UK Government, available at: https://www.gov.uk/government/publications/nationality-and-borders-bill-deprivation-of-citizenship-factsheet/nationality-and-bordersbill-deprivation-of-citizenship-factsheet. 39 ‘How many people have been stripped of their Briitsh Citizenship’ Free movement, available at: https://freemovement.org.uk/howmany-people-have-been-stripped-of-their-british-citizenship-home-office-deprivation/. 40Freedom of information request to the UK Home Office’ (2016), available at: https://www.whatdotheyknow.com/request/318785/response/827666/attach/3/CCWD%20FOI%2038734%20Final%20Response.pdf?coo kie_passthrough=1. 41 HM Government Transparency Report 2015: Disruptive and Investigatory Powers’ (2015), available at: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/473603/51973_Cm_9151_Transpare ncy_Accessible.pdf; ‘HM Government Transparency Report 2017: Disruptive and Investigatory Powers’ (2017), available at: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/593668/58597_Cm_9420_Transpare ncy_report_web.pdf; ‘HM Government Transparency Report 2018: Disruptive and Investigatory Powers’ (2018), available at: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/727961/CCS207_CCS04185382401_Transparency_Report_2018_Web_Accessible.pdf; ‘HM Government Transparency Report 2017: Disruptive and Investigatory Powers’ (2018/19), available at: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/919625/CCS0320317274001_HM_Government_Transparency_Report_Web_Accessible.pdf; ‘HM Government Transparency Report: Disruptive Powers 2020’ (2020), available at: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1058164/E02724471_CP_621_Web_ Accessible.pdf. 6