G. Application of the prohibition in UK domestic law 23. Against the background of that analysis, it then falls to the Court to apply the prohibition against the arbitrary deprivation of nationality as relevant to Ground 1 in these proceedings. However, the UN Special Rapporteur makes one additional observation as to the relevance of a rule of international law in domestic proceedings, which may assist the Court. 24. The Secretary of State appears to have assumed that the principles contained in Article 15(2) of the UDHR and Article 8(4) of the 1961 Convention are irrelevant, on the basis neither of them rises to the status of an incorporated treaty.54 However, an incorporated treaty is not the only source of international law relevant for purposes of interpretation of domestic law. As is well-settled law, “there is a strong presumption in favour of interpreting English law (whether common law or statute) in a way which does not place the United Kingdom in breach of an international obligation”,55 including obligations arising in treaties where they have not been incorporated in domestic law. This is because domestic law should ordinarily develop in harmony with the UK’s international obligations.56 It is principally on the basis of that presumption that the prohibition against arbitrary deprivation of nationality – a rule of international law binding on the UK – is engaged. 25. The UN Special Rapporteur hopes that these submissions will assist the Court in addressing the public international law issues before it. She respectfully remains at the Court’s disposal in the event that any further assistance can be usefully provided. GUGLIELMO VERDIRAME QC Twenty Essex JASON POBJOY Blackstone Chambers BELINDA McRAE Twenty Essex TESSA GREGORY TOM SHORT Leigh Day 29 May 2020 54 SGD, footnote 4. For the avoidance of any doubt, the UDHR is not a treaty, whether unincorporated or otherwise. R v Lyons [2002] UKHL 44, [2003] 1 AC 976, para. 27 (Lord Hoffmann). See also Assange v Sweden [2012] UKSC 22, [2012] 2 AC 471, paras 10 (Lord Phillips), 98 (Lord Brown); 112 (Lord Kerr); 122 (Lord Dyson). 55 R (SG) v Secretary of State for Work and Pensions [2015] UKSC 16, [2015] 1 WLR 1449, para. 241 (Lord Kerr). See also Keyu v Secretary of State for Foreign and Commonwealth Affairs [2015] UKSC 69, [2016] AC 1355, para. 150 (Lord Mance). See also R v Bow Street (Ex parte Pinochet) (No. 3) [2000] 1 AC 147, 276 (Lord Millett) regarding the relationship between common law and CIL (“Customary international law is part of the common law.”) 56 10

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