Section 4B of the British Nationality Act 1981 entitles people with British National (Overseas) citizenship to register as British citizens if they:
- do not have any other citizenship or nationality, and
- have not, since 19 March 2009, “renounced, voluntarily relinquished or lost through action or inaction any citizenship or nationality”.
One of those trying to invoke this provision was Hashim Tariq, who was born in Pakistan but also had BNO status. His citizenship saga began in 2010 with an unsuccessful application under section 4B. Eleven years on, the Home Office has prevailed: Secretary of State for the Home Department v Tariq  EWCA Civ 378.
The case turned on whether Mr Tariq could establish that he had not lost his Pakistani citizenship through inaction. A letter from the Pakistani consulate in Hong Kong stated that Mr Tariq ceased to be a Pakistani national when he acquired BNO status in 1997. Expert evidence, however, found that the letter was mistaken; Mr Tariq only lost his Pakistani citizenship when he turned 21, on 2 January 2010 (crucially, after the section 4B relevant date of 19 March 2009). Because Mr Tariq lost his Pakistani citizenship through inaction (his failure to renounce his BNO status by age 21), he failed to meet the section 4B criteria.
Thankfully for Mr Tariq, the new Hong Kong BNO visa route now offers him a route to settlement in the UK instead.