Mark Bullen spent eleven years as a police officer with Hertfordshire Constabulary. He was the force's only fluent Russian speaker, wrote its training material on Russian organised crime and prison tattoos (later published as Thief in Law), took part in an International Police Association exchange in St Petersburg in 2010, and organised professional visits the other way. Colleagues and the public gave him two officer-of-the-year awards and two commendations. He had a clean disciplinary record.

He had been fascinated by Russia since childhood, with no family connection to the place. He first visited at 18 in 1999, taught himself the language, and lived there for a period before returning to join the police. In 2014 he left the force and moved permanently to St Petersburg. He married a Russian woman, they have four children, and in 2022 he took Russian citizenship, calling it the fulfilment of a lifelong dream. He works in communications for Zenit St Petersburg, the Gazprom-owned football club.

Special Branch had asked him about his travel as early as 2013. In November 2024, returning from Turkey to visit family, counter-terrorism officers stopped him at Luton under Schedule 3 of the Counter-Terrorism and Border Security Act 2019 (powers aimed at hostile-state activity). Devices were seized, biometrics taken; he was questioned for hours, including about the 2018 Salisbury poisonings. He was released without charge. He says he was refused a lawyer despite asking three times.

In October 2025, shortly after Shabana Mahmood became Home Secretary, he received a deprivation order. Under section 40(2) of the British Nationality Act 1981 he was stripped of British citizenship because the Secretary of State was satisfied that deprivation was "conducive to the public good." The supporting material would not be disclosed "in the interests of national security." He is reported as the first British-born person to lose citizenship over alleged Russia links (two earlier cases involved people not born in the UK).

Bullen has repeatedly denied any wrongdoing. He points to his police record and says the idea that he is a threat to the UK is "comical." He has indicated he would appeal if legal aid were available, but has also said that, forced to choose, he would keep the Russian passport "without a second thought." The British embassy confirmed the notice was genuine and told him the appeal would be closed and secret: he would not see the evidence and would not know the precise accusation. Yes, 1984 is in Britain.

Outline of a Legal Defence Against the Deprivation

The power used is section 40(2) BNA 1981: the Secretary of State may deprive a person of citizenship if satisfied that deprivation is conducive to the public good. Because Bullen holds Russian nationality, the order does not leave him stateless, so the statutory bar in section 40(4) does not apply. (The exceptional power to render a naturalised citizen stateless under section 40(4A) is irrelevant here; he is British-born.)

Any appeal, once the decision is certified under section 40A(2) because of national-security material, goes to the Special Immigration Appeals Commission (SIAC), not the ordinary First-tier Tribunal. SIAC's role, as settled in Begum and U3, is not to decide the national-security question afresh. It reviews the Secretary of State's evaluative assessment on public-law grounds: whether it was irrational (Wednesbury), procedurally unfair, or otherwise unlawful. Substantial deference is given to the executive's assessment of risk, intelligence, and hostile-state activity. Closed material procedures apply; a special advocate sees the sensitive material but cannot share it with the appellant.

If I was defending Bullen the defence would focus on the following lines:

1.Rationality / evidential basis of the assessment
Argue that the decision rests on an assessment that is so thin, speculative, or based solely on lawful conduct (longstanding cultural affinity, legitimate police exchanges, residence, employment, dual nationality) that no reasonable Secretary of State could treat it as establishing a national-security risk sufficient for deprivation. Past Special Branch interest and the 2024 airport stop that produced no charge are relevant context but do not, by themselves, prove ongoing hostile activity. The absence of any criminal charge or conviction should be weighed.

2.Procedural fairness and the right to know the case

Emphasise the extreme opacity: no public reasons beyond the statutory formula, closed SIAC proceedings, and the practical inability of the individual (or even ordinary counsel) to test the underlying intelligence. While closed procedures are lawful in national-security cases, the defence can still argue that the combination of non-disclosure and the severity of the consequence falls below the minimum requirements of fairness recognised in the case law, or that the special-advocate regime is inadequate on these facts.

3.Proportionality and Article 8 ECHR
Deprivation interferes with private and family life (ability to visit family in the UK, identity, and the residual rights of a British citizen). Although national security is a powerful countervailing interest, the defence can argue that the interference is disproportionate given the lack of any disclosed concrete threat, Bullen's clean record, and the fact that he already lives permanently abroad. Article 8 does not prevent deprivation in genuine security cases, but it requires the decision-maker to address the balance explicitly and rationally.

4.Consistency and selective application
Note that many British citizens live and work in Russia (or for Russian entities) without losing citizenship. Argue that treating long-term residence, dual nationality, and a personal interest in Russian culture as sufficient, without more, risks turning a discretionary power into a general penalty for association with a hostile state. Precedent is limited and mostly concerns terrorism or serious organised crime; this case is presented as novel for a British-born dual national on Russia-related grounds.

5.Practical and temporal points
The 2024 stop was under investigative powers and ended without charge. The deprivation came nearly a year later. The defence can ask what new material, if any, justified the later step and whether the assessment properly distinguishes between historical professional contacts (while still a serving officer) and any subsequent conduct.

In practice, SIAC appeals against national-security deprivation decisions are difficult to win precisely because of the deference and the closed procedure. Success usually requires showing a clear public-law error: irrationality, failure to consider a relevant factor, or a material procedural defect, rather than simply disagreeing with the security assessment. Bullen's own comments suggest he understands the odds and the secrecy involved.

The case sits at the intersection of executive power over nationality, the treatment of dual nationals, and the post-2014 (and post-2022) security climate with Russia. Whether the undisclosed material would satisfy a reviewing court remains unknown to the public and, by design, to Bullen himself.

And above all this, an Englishman has his citizenship stripped by UK Home Secretary with the name Shabana Mahmood; welcome to multicult Britain:

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