The revocation of Shamima Begum's UK citizenship in 2019 was unlawful as the effectively stateless 'ISIS bride' would face the death penalty if sent to Bangladesh, her parents' country of origin, a court has heard.
The 23-year-old's legal appeal at the Special Immigration Appeals Commission (Siac) was told that the then home secretary, Sajid Javid, had failed to consider the "serious practical consequences" of removing Begum's UK citizenship in 2019, The Guardian reports.
In the hearing challenging the decision, her legal team said it ignored the fact that she may have been trafficked into Syria, adding she has been "banished".
Shamima Begum's UK citizenship was stripped after she travelled to Islamic State group-controlled Syria with two other east London schoolgirls - Kadiza Sultana, 16, and 15-year-old Amira Abase, when she was 15. There she married an Islamic State fighter and lived under IS rule for more than three years. She was found by the Times newspaper in a Syrian refugee camp in 2019.
The case is being heard at the Special Immigration Appeals Commission (SIAC), which has similar standing to the High Court, and can hear national security evidence in secret if necessary.
"It is clear that he gave no consideration to the prospect that the deprivation decision would render the appellant de facto stateless," Dan Squires KC, for Begum, told the hearing.
"There is nothing in any of the Home Secretary's evidence which suggests that consideration was given - prior to the deprivation decision being taken, or indeed at any time - to matters relating to de facto citizenship," Squires said, in submissions.
These matters included whether Begum would be recognised by Bangladesh as a citizen and provided with any protection or practical support, he said.
"The home secretary has not responded to the allegation that the decision-maker neither directed his mind to this issue nor took steps such as contacting the Bangladeshi authorities to find out their position regarding the appellant," Squires said.
Had such inquiries been carried out, "the Bangladesh authorities would have confirmed that the appellant would be hanged if she entered the country," Squires said.
He added: "This was their stark position in respect of the appellant as set out in the public statements of the Bangladeshi authorities immediately after the decision was taken."
In May 2019, Bangladesh's foreign minister confirmed Begum could face the death penalty for involvement in terrorism if she went to Bangladesh.
Begum's lawyers said: "It is clear that, had the home secretary made inquiries as to the practical effect of depriving the appellant of her citizenship, he would likely have understood that the appellant could be left without the protection of any state."
"It was, or ought to have been, known to the home secretary, that even where deprivation does not result in de jure statelessness, it may render a person de facto stateless, with extremely serious practical consequences."
The Home Office lawyers said that the argument "appears to amount to an assertion that the secretary of state is under a duty to seek the views of foreign governments before he decides whether to deprive one of their nationals of their British citizenship.
"Such an argument, were Siac to accept it, would have very serious consequences – indeed, it would likely render the entire deprivation regime inoperable."
The lawyers said it would be "relatively straightforward" for a foreign government to disavow that an individual either is a national or state that they would not be treated as one, even where that had no basis in the nationality laws of that state.