The “extraordinary and “extreme” decision to remove the British citizenship of Shamima Begum has condemned her to “exile for life” and should be overturned, a court was told on Monday as the former Bethnal Green schoolgirl began a new attempt to win back her passport.

Ms Begum’s barrister Samantha Knights KC told a hearing at the Special Immigration Appeals Commission in London that Ms Begum had been the victim of a “determined Islamic State propaganda machine” when it lured her to Syria in 2015 when she was a 15-year-old.

She said grounds for overturning the Home Office’s decision to remove her British citizenship on national security grounds included the fact that she had been a trafficking victim and the hasty way in which the former Home Secretary Sajid Javid had acted in removing her passport only a week after she gave a newspaper interview to reveal she was still alive and wanted to return.

Ms Begum’s lawyers are also contesting the decision to remove her citizenship on the grounds that the Home Secretary’s decision was pre-determined and disproportionate to the risk she posed.

Other among the nine grounds for her appeal include an argument that the decision to remove her passport was unlawful because the Bangladeshi citizenship that judges have previously ruled she possesses is effectively useless because its government will never allow her to live there.

Ms Knights said: "This case concerns a British child aged 15 who was persuaded, influenced and affected with her friends by a determined and effective Isis propaganda machine."

In written submissions, Ms Knights said there was "overwhelming" evidence that Ms Begum had been "recruited, transported, transferred, harboured and received in Syria for the purposes of 'sexual exploitation' and 'marriage' to an adult male".

"She was following a well-known pattern by which Isis cynically recruited and groomed female children, as young as 14, so that they could be offered as 'wives' to adult men," the barrister added.

But later A MI5 officer told the hearing MsBegum "in some respects...would have known what she was doing" when she travelled to Syria as a teenager to join a terror group.

Speaking from behind a screen, the officer said it was "worth remembering the context" of the terrorist organisation's acts around 2015.

The officer said the groups' actions around the time included large terror attacks and the public beheadings of multiple people - including journalist James Foley and aid worker Peter Kassig in 2014.

"It is inconceivable someone would not know what Isil was doing as a terrorist organisation at the time," they continued.

The witness noted Ms Begum was predicted high grades in her exams, suggesting she was "intelligent", "articulate" and likely capable of critical thinking".

They added: "In some respects yes, I do think she would have known what she was doing and would have had agency in doing so."

Ms Begum fled her east London home for Syria as a 15-year-old schoolgirl with Kadiza Sultana and Amira Abase to join the so-called Islamic State group (IS) more than seven years ago.

She has denied any involvement in terror activities and is challenging a Government decision to remove her citizenship, while Ms Sultana was reportedly killed in a Russian air raid and Ms Abase is missing.

It has since been claimed that she was smuggled into Syria by a Canadian spy.

A Special Immigration Appeals Commission hearing at Field House tribunal centre, London is expected to last five days.

In February 2019, Ms Begum was found, nine months pregnant, in a Syrian refugee camp. Her British citizenship was revoked on national security grounds shortly afterwards.

She challenged the Home Office’s decision, but the Supreme Court ruled that she was not allowed leave to enter the UK to pursue her appeal.

Last summer, during an interview, Ms Begum said she wanted to be brought back to the UK to face charges and added in a direct appeal to the Prime Minister that she could be “an asset” in the fight against terror.

She added that she had been “groomed” to flee to Syria as a “dumb” and impressionable child.

According to the BBC and The Times, Mohammed Al Rasheed, who is alleged to have been a double agent working for the Canadians, met the girls in Turkey before taking them to Syria in February 2015.

Both news organisations reported that Rasheed was providing information to Canadian intelligence while smuggling people to IS, with The Times quoting the book The Secret History Of The Five Eyes.

Begum family lawyer Tasnime Akunjee previously said in a statement: “Shamima Begum will have a hearing in the SIAC (Special Immigration Appeals Commission) court, where one of the main arguments will be that when former home secretary Sajid Javid stripped Shamima Begum of her citizenship leaving her in Syria, he did not consider that she was a victim of trafficking.

“The UK has international obligations as to how we view a trafficked person and what culpability we prescribed to them for their actions.”