Lawyers for 'ISIS bride' Shamima Begum say revoking someone's citizenship is "draconian" and has potentially "fatal" consequences.
Begum travelled to Syria to join so-called Islamic State in February 2015 and is engaged in a legal battle to allow her return home.
Ms Begum, now 20, lived under IS rule for more than three years before she was found heavily pregnant in a Syrian refugee camp in February last year.
Home Secretary Sajid Javid revoked her British citizenship later that month resulting in legal battle by lawyers who have argued that the move was unlawful.
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