In U3 (AP) v Secretary of State for the Home Department [2025] UKSC 19, the Supreme Court has unanimously dismissed an appeal against a decision taken by the Special Immigration Appeals Commission ("SIAC") relating to deprivation of citizenship and refusal of entry clearance on the basis of national security concerns.
Facts
The appellant, U3, was a British citizen prior to the events leading up to these proceedings. She, her previous husband, O, and her three children, who are also British nationals, had travelled to Turkey, then to ISIL-controlled territory in Syria between August 2014 and October or November 2017.
On 22 April 2017, the Home Secretary made an order under section 40(2) of the British Nationality Act 1981 to deprive the appellant of her citizenship on the ground that she was satisfied that deprivation was conducive to the public good. The notice of deprivation given to the appellant in accordance with section 40(5) of the 1981 Act stated,
it is assessed that you are a British/Moroccan dual national who has travelled to Syria and is aligned with ISIL. It is assessed that your return to the UK would present a risk to the national security of the United Kingdom.
That assessment was based on advice the Home Secretary had received from the Security Service and from the Special Cases Unit of the Home Office, some of which could not be made public. The appellant appealed against the deprivation decision. In 2019, the children were repatriated to the UK, where they were cared for by members of the appellant's family. The appellant remains in Syria with her present husband.
On 11 August 2020, the appellant applied to the Home Secretary for entry clearance granting her leave to enter the UK. On 18 December 2020, that application was refused. On 15 January 2021, the appellant appealed the entry clearance refusal to SIAC under section 2 of the Special Immigration Appeals Commission Act 1997 ("the 1997 Act"), on the ground that, since the decision prevented her from rejoining her children, it was an unjustified interference with her right to respect for family life (article 8, ECHR), and, thus, unlawful under section 6(1) of the Human Rights Act 1998.
Both appeals were heard together initially in the SIAC.
SIAC's Decisions
The Citizenship Deprivation Appeal
The focus of both appeals before the SIAC was on the Home Secretary's assessment that the appellant poses a risk to national security. It was the appellant's case that she poses no such risk and that the assessment was wrong.
The appellant relied on evidence said to show that, when she travelled to Turkey and Syria, she was in an abusive, coercive and controlling relationship with O, and she did not then know about ISIL's ideology or atrocities committed. She submitted she had not ever been ideologically aligned with ISIL, had not become radicalised in Syria, and did not support extremism in general.
The SIAC adopted the approach from R (Begum) v Special Immigration Appeals Commission [2021] UKSC 7 ("Begum") in that the Home Secretary's national security assessment could be challenged on any public law ground. However, distinct from the approach used in judicial review proceedings, evidence assessed does not have to be confined to that relating to matters occurring prior to the deprivation decision.
Deprivation decisions are often made, as in the case at hand, without giving the affected person any opportunity to make representations. Given that Parliament had conferred a right of appeal against deprivation decisions, the SIAC could not be precluded from taking into account the appellant's evidence that she was not a threat to national security.
In applying the Begum approach, there were multiple ways for the appellant's evidence to be taken into account, two of which are material for present purposes:
- Evidence relating to events occurring prior to the deprivation decision might identify the significance of a matter which the Home Secretary did not consider but ought to have considered.
- If an individual appeals against a deprivation decision, their national security assessment gets updated during appeal proceedings to take account of the appellant's evidence and any material uncovered by the review. The updated assessment then supersedes the original one for the purposes of the appeal. Thus, new evidence that is part of the updated assessment can be assessed on public law grounds, as promulgated in Begum.
The reason for this "rolling" approach to challenges to deprivation decisions, when it is disapproved of in regular judicial review proceedings, is due to the profound significance and serious implications of being deprived of one's citizenship.
In regards to the actual assessment of the evidence, the SIAC noted that the appellant's case in relation to national security rested on the proposition that she did not go to Syria with the intention of aligning with ISIL, and was not subsequently radicalised.
The SIAC considered that, despite accepting that the appellant had been subjected to serious and sustained violence, and coercive control, she was able to make reasoned decisions for herself and her children, and it remained possible that an ideological commitment to ISIL played a part in her decision to leave the UK for Turkey.
Moving on to the appellant's motivation for leaving Turkey for Syria, the SIAC found that the evidence included a number of elements which could suggest that the appellant was ideologically aligned with ISIL when she did so citing, for example, social media posts of the appellant which included quotations from extremists and supporters of ISIL.
Finally, despite the appellant's evidence providing a strong basis for her case that she was very quickly disillusioned with ISIL and would have left its territory if she could, the closed evidence cast doubt on that assertion.
The SIAC concluded that the Home Secretary could rationally assess, at the date of the deprivation decision, that the appellant was ideologically aligned with ISIL when she left for Turkey, and continued to be so aligned thereafter such that she posed a risk to the national security of the UK. In those circumstances, it did not matter whether the SIAC agreed with that view. The deprivation decision was not vitiated by any public law error.
The Entry Clearance Appeal
It was the SIAC's view that the reasoning given by the Home Secretary gave a rational basis for concluding that the appellant remained ideologically aligned when she left ISIL-controlled territory. Accordingly, SIAC concluded that it was rationally open to the Home Secretary to conclude that the appellant continued to pose a danger to national security at the date of the entry clearance decision and at the date of the appeal hearing.
The SIAC then balanced this conclusion with the intrusion to the article 8 rights of the appellant's children (the appellant herself being outside the jurisdictional scope of the Convention as she was not in the territory of the UK at the time of either of the Home Secretary's decisions, nor did she fall within any of the categories of non-territorial jurisdiction). It found that the children were currently well cared for and that, given the appellant could face criminal prosecution on return to the UK, it could not be assumed that she would simply resume her role as primary carer if she returned. The court concluded that the children's rights under article 8 were firmly outweighed by the Home Secretary's assessment that the appellant posed a risk to national security: an assessment which SIAC had found to have a reasonable basis in the evidence. The entry clearance appeal was therefore dismissed.
Court of Appeal
Lady Justice Laing upheld the SIAC's approach to appeals under section 2 or 2B of the 1997 Act. However, she took a broader view of the SIAC's role, holding that SIAC can make findings of fact on the balance of probabilities where appropriate, and such fact finding could contradict and displace a finding made by the Home Secretary, if that finding was "pivotal".
The Court found an error in the judgment of first instance, stating that the SIAC could have made a finding of fact on the question of whether the appellant had freely remained in ISIL-controlled territory. However, it was concluded that this error was immaterial as this factor alone would not have undermined the Home Secretary's assessment of risk.
The Court subsequently endorsed the SIAC's approach of carefully evaluating all the evidence in the case, applying public law principles to the appellant's challenge to the Home Secretary's assessment of the threat she posed to national security, and refraining from substituting its own national security assessment for that of the Home Secretary.
The appeal was dismissed.
Supreme Court
The Supreme Court unanimously dismissed the appellant's appeal, with Lord Reed giving the lead judgment.
The key issue to be determined in both appeals was that of the SIAC's role in relation to the Home Secretary's assessment of the risk posed by the appellant to national security.
The Court began by reiterating the clear distinction between an appeal of this sort to the SIAC and judicial review, confirming that appeals under sections 2 and 2B of the Special Immigration Appeals Commission Act 1997 are appeals in substance and form. Unlike judicial review, they may involve the determination of questions of fact and law and are not confined to evidence available to the Home Secretary at the time of the impugned decision. The Court clarified that where the decision is based on the Home Secretary's national security assessment, that assessment is kept under review by the Home Secretary throughout the appellate proceedings. The SIAC then treats this updated assessment as superseding the original. When making a finding of fact, the Court does so on the balance of probabilities, in accordance with the general rule governing civil proceedings.
However, and pertinently to the case at hand, the Court noted that not every issue which the SIAC may have to decide in an appeal can be determined by making findings of fact on a balance of probabilities. When assessing whether someone is a risk to national security, a different approach is required. This is for a number of reasons.
First, it is due to the nature of assessing risk. Assessment of risk is based on an evaluative judgement or assessment that an unacceptable risk exists, not on the existence of a particular fact or the occurrence of a particular event. A risk is a possibility and, thus, can arise from evidence which is sufficient to establish a possibility but falls short of proof on a balance of probabilities. National security assessments may rely on fragments of intelligence or information that, taken cumulatively, justify apprehension, even if no single element is conclusive. Within the context of terrorist attacks in recent memory such as the Manchester Arena Bombing, a precautionary approach was deemed necessary by the Court given how catastrophic the consequences of a mistake could be.
Secondly, the SIAC is not the primary decision maker in deprivation decisions, the Home Secretary is, and it is a discretionary power. It is a general principle on discretionary powers that court will not interfere with a decision merely because it might itself have decided the matter differently, provided the decision is one that could reasonably be taken. Institutionally, the Home Secretary acts on the basis of expertise which judges do not possess. Additionally, as a matter of the Constitution, decisions which have serious potential results for the community should be the responsibility of a member of the government who is accountable to Parliament, and ultimately to the electorate, as Lord Hoffman espoused Secretary of State for the Home Department v Rehman [2001] UKHL 47 at [62] in a postscript to his speech written after the 9/11 attacks on the United States:
Such decisions, with serious potential results for the community, require a legitimacy which can be conferred only by entrusting them to persons responsible to the community through the democratic process
The Supreme Court identified one error in the SIAC's reasoning: it was incorrect to proceed on the basis that the issue to be decided was the rationality of the deprivation decision at the time it was made. As the national security assessment is updated during the appeal to reflect the appellant's new evidence and submissions, the SIAC must consider the rationality of the re-affirmed decision as it stands at the time of the hearing. This includes evidence arising after the original decision, which may bear on whether deprivation remains appropriate.
However, this misunderstanding had no material effect on the outcome. The SIAC considered the evidence in question in relation to the appeal against the refusal of entry clearance, and concluded that, even having regard to that evidence, the Home Secretary's assessment of the risk posed by the appellant to national security could not be regarded as irrational or otherwise flawed in any administrative law sense.
Turning to the Court of Appeal judgment, the Supreme Court ruled that it was incorrect that the issue the SIAC has to decide is whether the assessment is based on facts that have been established on a balance of probabilities. Rather, the central question is whether the evidence, viewed as a whole, provides a rational basis for the Home Secretary's decision, applying principles of administrative law.
In regard to the human rights aspect, the appellant argued that the public law approach to issues of national security adopted in Begum, and in the present case, meant that SIAC's procedures no longer met Convention standards. The Court did not find this submission persuasive, on the basis that, even in relation to issues of national security, it was of the view that the SIAC is able to carry out a rigorous scrutiny of the Home Secretary's assessment through public law grounds. It cited case law, such as Ramos Nunes de Carvalho e Sá v Portugal (Applications Nos 55391/13, 57728/13 and 74041/13) 6 November 2018, which emphasised that the procedural requirements of the Convention do not invariably necessitate that an appellate tribunal must have the ability to substitute its own assessment or opinion for that of the administrative authority, especially given the institutional and constitutional competency of such authorities.
Comment
This judgment continues the strict approach to deprivation of citizenship appeals established in Begum, in which deference to the executive on matters of national security appears to take precedence over individual rights. While the Court emphasised that the SIAC can assess whether there is a rational basis for the Home Secretary's conclusions, it confirmed that it cannot substitute its own factual assessments, even where persuasive new evidence is presented. This narrow framework reflects the legacy of the hostile environment policy and, more broadly, the global war on terror in which individual rights, particularly of marginalised people, are increasingly subordinated to executive discretion. Like Begum, this case has a gendered dimension as both judgments limit the available remedies for women who have experienced abuse or trafficking by limiting their ability to return to the UK. This pattern of cases raises important concerns about access to justice and the erosion of protection for vulnerable individuals under national security frameworks.