Introduction

The Deprivation of Citizenship (Effect during Appeal) Act 2025 received the Royal Assent on 27 October 2025 and came into force the same day. It had been introduced in the House of Commons on 19 June 2025. It is a slight thing, with two sections, designed to rectify what the Government considers an unintentional consequence of the Supreme Court’s judgment in N3(ZA) v Secretary of State for the Home Department [2025] UKSC 6. In that case the Supreme Court had considered the consequence of a successful appeal against a decision that the Secretary of State was satisfied that deprivation of citizenship was conducive to the public good. As a result of that judgment, a successful appellant had their British citizenship restored automatically after success on appeal at first instance, notwithstanding the possibility of onward appeal by the Secretary of State. This Act postpones that moment of automatic restoration of citizenship until all onward appeal rights have been exhausted.

N3(ZA) v Secretary of State for the Home Department [2025] UKSC 6

In N3(ZA), ZA is the child of a man, E3, who had been deprived of British citizenship on the grounds that the Secretary of State was satisfied that deprivation of citizenship was conducive to the public good under section 40(2) of the British Nationality Act 1981 (‘1981 Act’). As the decision was made on grounds of national security, E3’s right of appeal was displaced from the First-tier Tribunal to the Special Immigration Appeals Commission (‘SIAC’) (see s. 40A(2)(a) of the 1981 Act and s. 2B Special Immigration Appeals Commission Act 1997).

Having made the decision to deprive E3 of his British citizenship, the Secretary of State proceeded to make the deprivation order itself. In consequence, during his appeal E3 was not a British citizen. Thereafter, as a result of the development of the law in another case (C3, C4 and C7 v Secretary of State for the Home Department (SC/167/2020, SC/168/2020 and SC/171/2020), the Secretary of State conceded the appeal and withdrew the deprivation decision; thus, she said, reinstating British citizenship.

However, the Secretary of State maintained that the deprivation orders were lawful at the time they were made and that E3 had not been a British citizen thereafter until the deprivation order was withdrawn. Such a stance protected the Secretary of State’s immigration enforcement action during the period of deprivation and thus, for example, precluded any challenge to the lawfulness of detention during that period by way of a claim for judicial review or habeas corpus, or an action in tort for false imprisonment.

On the other hand, it prejudiced E3’s child, ZA, who had been born in the UK during that period. Were the effect of a withdrawal of a deprivation order or successful appeal to SIAC to mean that the deprivation order was unlawful from the outset, ZA would have automatically acquired British citizenship by virtue of birth in the UK to a parent who was a British citizen (having been born in the UK, E3 was a British citizen otherwise than by descent) under s.  2(1)(a) of the 1981 Act.

Thus, the effect of a successful appeal at first instance was put in issue. Judicial review challenges failed before the High Court and the Court of Appeal. Then the case arrived in the Supreme Court. 

The Supreme Court considered that the question to be answered was: ‘…what is the effect on the deprivation order of the outcome of the appellate proceedings. In the light of the outcome of the appellate proceedings, is the deprivation order to be treated as: (a) a nullity from the outset; (b) only having no effect from the date of the outcome of the appellate proceedings; or (c) having some effects only from the date of the outcome of the appellate proceedings and some effects from the outset?’ (per Lord Sales and Lord Stephens, with whom Lord Reed, Lord Hodge, and Lord Lloyd-Jones agreed, at §9).

When considering the effect of a deprivation appeal to the First-tier Tribunal or SIAC, the Supreme Court stated, ‘… If the appeal is allowed by the appellate body, then the Secretary of State is bound by that court’s decision in accordance with the rule of law and as the matter would be res judicata between the parties. For instance, if the appellate body finds that the person concerned would be rendered stateless then, at that stage, the Secretary of State is bound by that decision’ (§38).

However, there are no statutory provisions that identify the consequences of a successful SIAC appeal against the decision to make a deprivation order or that require the Secretary of State to implement a decision on appeal, as the 1981 Act operates on the basis that the ‘ordinary principles governing the effect of an appeal will apply’ (§§50-51). The Supreme Court noted, ‘under ordinary principles a court order takes effect from the date of the order. The practice in SIAC is in many cases to allow a judgment to stand as the order to give effect to it, so that the date of the judgment is the relevant date’ (§39).

In giving judgment, the Supreme Court held that a successful appeal meant that, under the particular contours of the statutory scheme in the 1981 Act, and given the UK’s obligation under the Statelessness Convention, British citizenship had never been lost but that the Secretary of State’s officials were nonetheless protected as regards the immigration enforcement action taken in the period between the deprivation order and the withdrawal of the same or the appeal being allowed. It held:

‘[t]he statutory provisions should be given effect to achieve the purpose for which they were enacted, namely to provide legal protection for the Secretary of State and his or her officials in relation to immigration enforcement action taken on the basis of a deprivation of citizenship according to his or her order; but they should only be given that effect, and not the wider effect… Once SIAC determines that recognition of the validity of the deprivation order would render the individual stateless and it allows the appeal against it (or the Secretary of State concedes that SIAC must allow the appeal), then for the purpose of determining the individual’s status in the period from the date of the making of the order until the appeal is allowed (as distinct from the purpose of deciding whether immigration enforcement action taken in that period on the basis of that order was unlawful) the order is to be treated as having no effect’ (§90).

It went on:

‘Once SIAC makes its determination that a deprivation order would make an individual stateless and accordingly allows the appeal against it, nothing more is required to be done. The Secretary of State is simply bound by that determination for all purposes (other than in respect of the validity of immigration enforcement action taken on the basis of the deprivation order up to the time the appeal against it is allowed)… the matter is res judicata so far as concerns the Secretary of State, who is therefore not entitled to deny that the individual remained a British citizen throughout the whole period after the making of the deprivation order, with all that this entails’ (§92).

As can be seen, it is from the date of the first instance appeal judgment (here, of SIAC rather than the First-tier Tribunal) that time runs. As above, there is no order to appeal as the ‘practice in SIAC is in many cases to allow a judgment to stand as the order to give effect to it, so that the date of the judgment is the relevant date’ (§39).

The Deprivation of Citizenship Orders (Effect during Appeal) Act 2025

The Deprivation of Citizenship Orders (Effect during Appeal) Act 2025 inserts provisions into section 40A of the 1981 Act, the latter already providing for deprivation of citizenship appeals. The new sub-sections provide that where a deprivation of citizenship order is made under section 40 of the 1981 Act, and the person concerned appeals to the First-tier Tribunal or to SIAC, the order continues to have effect during the ‘appeal period’.

The ‘appeal period’ begins on the day the person appeals against the deprivation decision, or if the order is made thereafter, the day on which the deprivation order itself is made.

The ‘appeal period’ ends on the day on which the appeal is ‘finally determined, withdrawn or abandoned’. The end point is expressly defined as follows: ‘an appeal is not finally determined until the decision on the appeal, or on any further appeal, may not be overturned on a further appeal (ignoring the possibility of an appeal out of time with permission).’

By such means, Parliament has altered one effect of the Supreme Court’s judgment. No longer does a successful appeal before SIAC or the First-tier Tribunal (as the case may be) have the effect of the deprivation of citizenship order being treated as unlawful for the limited specified purposes given by the Supreme Court from the outset. Instead, that moment is postponed until the exhaustion of all onward appeal rights. This Act does not alter the fact that if the appeal against the decision to make a deprivation decision is ultimately successful once finally determined, a person will have remained a British citizen during the appeal period.

The Act extends to all parts of the United Kingdom, the Channel Islands, the Isle of Man, and the British overseas territories. This is consistent with the reach of the 1981 Act. The Act will came into force on the day it was passed, 27 October 2025.

In the Explanatory Notes to the Bill as it was introduced to Parliament,  the Secretary of State made clear her motivation for the Bill:

‘7. The implications of this [i.e., of British citizenship being restored automatically on a successful first instance appeal] are significant, particularly in cases where a decision to deprive citizenship has been made on the basis that the person poses a threat to national security. A person who may be overseas may seek to enter the UK or to renounce any other nationality they hold before the Home Office has had an opportunity to exhaust the appeal process.’ (Deprivation of Citizenship Orders (Effect during Appeal) Bill, Explanatory Notes (Bill 268—EN)).

From a citizen’s rights perspective, citizenship deprivation while outside the UK is wrong in principle, as well as being injurious as a matter of international law to a state that admitted that person on production of a valid UK passport. From the Secretary of State’s perspective, Parliament had already legislated to render lawful such action and an intended consequence of the Supreme Court’s judgment ought not to frustrate that status quo.

Retrospectivity in the Act

The Act makes express provision for retrospective application of the changes to a pending appeal. It applies to an appeal brought but not finally determined, withdrawn or abandoned, before the day on which the Act is passed. While it may be a principle of legal policy that a change to the law should not apply retrospectively, this yields in relation to procedural matters of which the provision made in this Act is an example.

Moreover, there is a general presumption that changes to procedure apply to pending as well as prospective proceedings. The thinking is that procedural rules enable justice to be done between the parties, consistently with the public interest.

Further, in any event, the matter is put beyond doubt by the express wording of the Act. There is no limit on Parliament’s power to make such express provision for retrospectivity, as it seeks to do so here. The presumption against retrospectivity does not impede the making of such a law.

Why not simply ask for a stay when appealing?

At first blush, one might ask the question, if the Secretary of State is disappointed with an appellant’s appeal allowed in SIAC or the First-tier Tribunal, and thereafter seeks to appeal herself, why does she not apply for a stay of its effect from the relevant tribunal or court from which permission to appeal is being sought? However, a number of problems present themselves.

First, as the Supreme Court noted, there are no statutory provisions dealing with the powers of SIAC (or indeed the First-tier Tribunal) on an appeal against the decision to make a deprivation order. Sections 40 and 40A of the 1981 Act do not identify the consequences of a successful appeal. Thus, it is pointless to search for an appealable order or direction made in consequence of an appeal being allowed. That said, as the Supreme Court noted, the practice in SIAC is to allow a judgment to stand as the order to give effect to it, so that may not be an insuperable obstacle.

Second, the procedural rules for the First-tier Tribunal (and on appeal from it, the Upper Tribunal), as well as those of SIAC, do not assist in making provision to apply for a stay, a position that appears to accord with the statutory basis on which they are made.

Third, as regards an appeal to the Court of Appeal, Civil Procedural Rule 52.16, which makes provision for a stay, applies only to an appeal from the Upper Tribunal and not from the SIAC: ‘Unless— (a) the appeal court or the lower court orders otherwise; or (b) the appeal is from the Immigration and Asylum Chamber of the Upper Tribunal, an appeal shall not operate as a stay of any order or decision of the lower court.’  Note, this provision applies to Upper Tribunal immigration appeals as well as British nationality appeals. Even as regards the Upper Tribunal, the precise statutory basis in current tribunal legislation from which this rule derives its validity is unclear. There have been several reforms to the statutory immigration appeal structure since the first iteration of the rule.

However, in certain circumstances, from the time the Notice of Appeal is filed, the Court of Appeal may exercise its inherent jurisdiction, not so as to order a stay within proceedings but rather to preserve the status quo, see for example YD (Turkey) v Secretary of State for the Home Department [2006] EWCA 52, [2006] 1 WLR 1646. Thus, in an appeal by the Secretary of State from SIAC to the Court of Appeal against an appellant’s successful citizenship deprivation appeal, there may be an option for her to seek a stay of the effect of the judgment. This would be in accordance with ordinary principles of justice and has scope to afford her a remedy. No doubt the Secretary of State has considered it safer to proceed by legislation, notwithstanding the possibility of a common law remedy.