The decision to remove Shamima Begum’s British citizenship was “unlawful”, the Court of Appeal heard on Tuesday, as her latest appeal against the decision began.

The Court of Appeal in London held a three-day hearing surrounding the decision to strip Shamima Begum of her British citizenship in 2019.

The hearing began on Tuesday, November 24 and ended on Thursday, with the final day of proceedings held in private.

Shamima Begum, now 24 years old, garnered international attention when she left the UK to travel to Syria in 2015 at the age of 15.

Her British citizenship was subsequently revoked on national security grounds, under the tenure of then-Home Secretary Sajid Javid, shortly after she was discovered in a Syrian refugee camp in February 2019.

Earlier this year, Begum lost a challenge against the decision at the Special Immigration Appeals Commission (SIAC).

In the latest case, Begum’s lawyers brought a bid to overturn this decision at the Court of Appeal, with the Home Office opposing the challenge.

Begum’s legal team argued on Tuesday that it was “unlawful” to deprive her of her British citizenship, primarily due to her status as a victim of trafficking at the time of her departure from the UK to join the Islamic State terrorist group in Syria.

Representing Begum, Samantha Knights KC told the court the government had failed to consider the legal duties owed to Begum as a potential victim of trafficking or as a result of “state failures” in her case.

She said in written submissions: “The appellant’s trafficking was a mandatory, relevant consideration in determining whether it was conducive to the public good and proportionate to deprive her of citizenship, but it was not considered by the Home Office. As a consequence, the deprivation decision was unlawful.”

At the hearing on Wednesday, Sir James Eadie KC, for the Home Office, said that decisions over whether someone is a victim of trafficking or whether they should be deprived of their citizenship “have fundamentally different bases and roles”.

The Home Office’s legal team defended the decision to revoke Begum’s citizenship, asserting: “Ms Begum contends that national security should not be a ‘trump’ card. But the public should not be exposed to risks to national security because events and circumstances have conspired to give rise to that risk.”

The hearing in London concluded on Thursday, with the final day of the proceedings held in private.

At the end of Wednesday’s session, the Lady Chief Justice Lady Carr said: “We anticipate we will be reserving both open and closed decisions.”