What does the new law on deprivation of British citizenship do?

The Deprivation of Citizenship Orders (Effect during Appeal) Act 2025 received Royal Assent on Monday this week. I wrote up the Bill when first introduced and it has passed unamended since then. The Act was brought in as a response to N3 v Secretary of State for the Home Department [2025] UKSC 6 (our write up is here) which said that where an appeal against deprivation of citizenship is successful, the initial deprivation order will be treated as though it had no effect, meaning that the person retained their British citizenship even where the Home Secretary may seek to appeal the decision.

The new law means that a person who has succeeded in their appeal against a deprivation order and who previously would have had their British citizenship reinstated at that point as though the deprivation had never been made, will not have their citizenship reinstated until the Home Secretary has exhausted her appeal rights. Or, if you’re the Home Office “Loophole closed to keep terrorists and extremists out of the UK”.

The Home Office published a factsheet yesterday which says that:

there are strong justifications for preventing a person regaining their British citizenship until all further appeals are determined, withdrawn, or abandoned. These include:

• preventing a person who is outside the UK and who poses a risk to the UK’s national security from returning until further appeals have been determined;
• preventing a person who has been deprived of citizenship on the grounds that it is conducive to the public good from renouncing their other nationality and putting themselves in a position whereby, if further appeals are successful, a further deprivation order would render them stateless;
• preventing another state from interfering with the UK’s use of deprivation powers by their removal of the person’s alternative citizenship so that if further appeals are successful, a further UK deprivation order would unlawfully render the person stateless; and
• allow for the use of immigration powers such as detention and immigration bail while an onward appeal is outstanding.

The second bullet point refers to a concern (I don’t know to what extent it is well-founded) of the Home Office about dual nationals “frustrating” the deprivation of their British citizenship by renouncing their second nationality before the Home Office was able to effect deprivation (a bit more on that here). The intention is presumably that British citizenship will be removed first, meaning the person is then unable to renounce their sole remaining nationality (as to do so would mean that country allowing them to become stateless, assuming of course that the second country is concerned about such an outcome).

On the final bullet point – the Supreme Court expressly held in N3 that immigration enforcement actions carried out between the deprivation decision and the successful appeal would have been lawfully carried out and that this could be distinguished from the person’s status. However that would not have covered the period following a successful appeal, and so now the position is that a person could have succeeded in an appeal against the deprivation of their citizenship but still be potentially subject to detention and immigration bail.