UK Home Secretary Shabana Mahmood has vowed to “robustly defend” the Conservative Party’s decision to revoke the citizenship of a British woman who fled to Syria as a 15-year-old to join the Islamic State (IS) group after a European Court challenged the move.

A government source told the BBC that Mahmood will defend the decision to strip Shamima Begum of her citizenship after the European Court of Human Rights (ECHR) asked the Home Office whether ministers considered Begum was a victim of trafficking.

“The home secretary will robustly defend the decision to revoke Shamima Begum’s citizenship, which has been tested and upheld time and again in our domestic courts,” said the source.

“The home secretary will always put this country’s national security first.”

Last December, the Strasbourg court sent a series of questions to the UK government, asking whether it broke anti-trafficking obligations when it stripped Begum of her citizenship in 2019.