What is Shamima Begum’s citizenship status right now?

According to the UK government, she is no longer a British citizen. The Home Office wrote to Begum’s parents on 19 February saying they had made the order to remove her citizenship that day.

How can they do that?

The government’s reasons, or how they might argue the action was legal, are not known. International law makes clear a person’s citizenship can not be revoked if doing so would make them stateless. So the Home Office evidently believes Begum either currently holds or is eligible to apply for citizenship of Bangladesh, from where her parents originate, in accordance with article 40 of the British Nationality Act 1981.

Can she?

Begum insists not – she says she has never held or applied for Bangladeshi citizenship, and she has never been to country. The Bangladeshi government has been even more explicit, insisting she is not a citizen and there is “no question” of her being allowed to enter.

What do the legal experts say?

Experts with knowledge of the British and Bangladeshi legal systems are divided on whether the Home Office’s action is legal. Fahad Ansari, a lawyer who acted for two men in a similar case, has said the UK-born children of Bangladeshi parents are automatically dual citizens at birth, but that right lapses at the age of 21. The government lost that case, but only because the two men were over 21, which would not apply to Begum, who is 19.

But Najrul Khasru, a British-Bangladeshi barrister and part-time tribunal judge who has reviewed Bangladesh’s citizenship laws, told the Guardian he believed Begum was not a Bangladeshi citizen unless, at the time of her birth, her parents had registered her at the High Commission, which he said was very uncommon within the British-Bangladeshi community.

The Guardian understands Begum’s parents say they did not register her birth in this way. It’s now up to the courts to decide. Begum family’s lawyer has confirmed they wish to appeal the removal of her citizenship, which could be a lengthy process.

What about her baby?

Crucially, Begum’s baby son, still less than a week old, was born before the order to strip her nationality was lodged, meaning he is British and his rights are unaffected, Sajid Javid indicated on Wednesday. The child therefore has the right to return to the UK, but the practicalities would be extremely complicated, as he won’t have UK identity documents.

Begum’s family are now exploring the legal and practical possibilities of bringing the baby to Britain, if his mother consents, while she awaits the outcome of any appeal in her case.