Deprivation of Citizenship on National Security grounds

The case U3 v Secretary of State for the Home Department [2025] UKSC 19 is a significant UK Supreme Court decision concerning the deprivation of British citizenship on national security grounds.

Background

The appellant, anonymised as U3, was a British-Moroccan dual national who traveled to Syria in 2014 with her husband and three children, residing in ISIL-controlled territory until late 2017. In April 2017, the Home Secretary issued a notice under section 40(5) of the British Nationality Act 1981, indicating the intention to deprive U3 of her British citizenship on the grounds that it was conducive to the public good. The decision was based on assessments that she was aligned with ISIL and posed a threat to UK national security. A national security certificate under section 40A(2) was issued, directing any appeal to the Special Immigration Appeals Commission (SIAC) .

U3 appealed the deprivation decision to SIAC in May 2018. In 2019, her children were repatriated to the UK and have since been cared for by relatives. In August 2020, U3 applied for entry clearance to return to the UK, which was refused in December 2020. She appealed this refusal on Article 8 grounds, arguing that it unjustifiably interfered with her right to family life. SIAC dismissed both appeals in March 2022, finding no public law error in the Home Secretary’s assessment that U3 posed a national security risk .

Legal Issues

The Supreme Court considered the following key issues:

  1. Scope of SIAC’s Review: Whether SIAC should make its own findings of fact in appeals against deprivation of citizenship on national security grounds, or limit its review to assessing the rationality of the Home Secretary’s decision.
  2. Application of Precedents: How the principles established in R (Begum) v Special Immigration Appeals Commission [2021] UKSC 7 and Secretary of State for the Home Department v Rehman [2001] UKHL 47 affect SIAC’s role in such cases.
  3. Article 8 ECHR: Whether the refusal of entry clearance unjustifiably interfered with U3’s right to family life under Article 8 of the European Convention on Human Rights.

Supreme Court Decision

In May 2025, the Supreme Court dismissed U3’s appeal, upholding the decisions of SIAC and the Court of Appeal. The Court held that:

  • SIAC’s Role: SIAC’s function is to assess whether the Home Secretary’s decision was lawful, not to substitute its own assessment of national security risks. While SIAC can consider new evidence, its role is to determine if the decision was one that the Home Secretary could reasonably have made, given the evidence available .
  • Deference to Executive Assessment: The Court emphasized that decisions on national security involve evaluative judgments for which the Home Secretary bears primary responsibility, supported by expert advice, including intelligence from the Security Service. SIAC must give “very considerable weight” to the Home Secretary’s assessment in such matters .
  • Article 8 Considerations: The interference with U3’s family life was deemed proportionate, given the national security concerns. The Court noted that while the best interests of the children are a primary consideration, they do not automatically outweigh other factors, such as the risk posed by the appellant .

Broader Implications

This judgment reinforces the principle that the deprivation of citizenship on national security grounds is a matter primarily for the executive, subject to judicial oversight to ensure legality and rationality. It clarifies that SIAC’s role is not to conduct a full merits review but to assess whether the Home Secretary’s decision falls within the range of reasonable responses.

The case also highlights the challenges individuals face in contesting deprivation decisions, especially when they have had limited opportunities to present their case before the initial decision. Organizations like JUSTICE have expressed concerns about ensuring that appellants have a meaningful opportunity to challenge such decisions, emphasizing the importance of procedural fairness and the right to be heard .

This case underscores the delicate balance between national security considerations and individual rights, particularly in the context of citizenship deprivation.

Disclaimer: The information in this blog is for general information purposes only and does not purport to be comprehensive or to provide legal advice. Whilst every effort is made to ensure the information and law is current as of the date of publication it should be stressed that, due to the passage of time, this does not necessarily reflect the present legal position. Privity Legal and authors accept no responsibility for loss that may arise from accessing or reliance on information contained in this blog. For formal advice on the current law please don’t hesitate to contact Privity legal. Legal advice is only provided pursuant to a written agreement, identified as such, and signed by the client and by or on behalf of Privity Legal.

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