Shamima Begum, the British-born national who travelled to Syria as a schoolgirl to join ISIL (ISIS), has lost her latest appeal against the removal of her citizenship.

Her lawyers on Wednesday vowed to keep fighting, saying the case was “nowhere near over”.

The British government stripped Begum of her citizenship in 2019, shortly after she was found in a detention camp in Syria.

Public opinion is divided over her case. Some say she should remain barred, while others believe she should stand trial in a British court for joining ISIL.

Here’s what you should know about the case:

Who is Shamima Begum?

Begum was born in 1999 in east London to parents of Bangladeshi heritage.

She is one of three schoolgirls who travelled in 2015 to ISIL-controlled Syria. She was 15 at the time.

In Syria, she married an ISIL fighter and had two children, both of whom died as infants.

Her British citizenship was revoked on national security grounds shortly after she was found nine months pregnant in a Syrian refugee camp in February 2019.

In an interview with The Times newspaper in 2019, Begum said she was tired of life on the battlefield and feared for her unborn child. That baby, named Jarrah, ultimately died from pneumonia later that year.

Begum, now 23, is being held at the al-Roj camp, in Syria’s northeast, which is home to more than 2,000 people.

She has pleaded with the United Kingdom’s government to be repatriated with her family in London.

Why and how did Begum lose her UK citizenship?

Citizenship is a legal status that “means a person has a right to live in a state and that state cannot refuse them entry or deport them”, according to the Migration Observatory of the University of Oxford.

This status may be conferred at birth or, in some states, obtained “through naturalisation”.

In 2019, a British judge said, however, that British citizenship is “not an absolute entitlement for everyone. It can be removed by the Secretary of State, but not if to do so would render the subject stateless”.

In Begum’s case, a UK tribunal ruled in 2019 that removing her citizenship was lawful because Begum “holds Bangladeshi citizenship” by descent through her parents.

Bangladesh denied this and said she would not be allowed in the country.

In 2019, the UK’s then-Home Secretary Sajid Javid also vowed to prevent anyone who joined ISIL from returning and said Begum was a threat to national security.

“You are a British/Bangladeshi dual national who, it is assessed, has previously travelled to Syria and aligned with ISIL. It is assessed that your return to the UK would present a risk to the national security of the United Kingdom,” a letter sent to her family in 2019 by the Secretary of State’s Private Office read.

Begum has never held Bangladeshi nationality and has never visited Bangladesh – and officials in the South Asian nation have said they will not issue her citizenship.

“I have one citizenship … and if you take that away from me, I don’t have anything. I don’t think they are allowed to do that,” Begum told the BBC in 2019.

“This is a life-changing decision; they haven’t even spoken to me.”

Victim of trafficking

Three Court of Appeal judges ruled in 2020 that Begum should be allowed back into the UK to challenge the revocation.

However, the case was taken to the Supreme Court, which ruled in 2021 that while Begum has a right to challenge the decision, she should do so from outside the UK due to “security concerns”.

Begum’s legal team accused the Home Office – the UK’s interior ministry – of failing to investigate whether she was a “child victim of trafficking”.

On February 2023, the judge ruled that a finding that Begum may have been trafficked was insufficient for her appeal to succeed.

“The implication, the outcome, that we face is that no British child who has been trafficked outside the UK will be protected by the British state if the home secretary invokes national security,” her lawyer Daniel Furner said after the decision.

Begum’s lawyers have argued that Begum and her friends’ entry into Syria had been facilitated by a Canadian agent working for ISIL.

A book released in August last year investigating intelligence sharing between the UK, Canada and other allies alleged that the Canadian agent’s role in Begum’s case was later covered up by the police and Britain’s security services.

The Secret History of the Five Eyes by Richard Kerbaj, a former security correspondent of The Sunday Times, prompted demands for an official inquiry into Begum’s case. Canada and the UK declined to comment on the allegations, as is routine for security issues involving intelligence agencies.

What comes next?

Furner told reporters that his team “will be challenging the decision” of Wednesday’s ruling.

Begum will have to take the case directly to the Court of Appeal in London if she wishes to challenge the decision, according to legislation that covers the tribunal.

“Her lawyers have even suggested it could go to the European Court of Human Rights, too,” said Al Jazeera’s Nadim Baba, reporting from London.

A spokesperson for Britain’s interior ministry, the Home Office, welcomed the ruling.

“The government’s priority remains to maintain the safety and security of the UK, and we will robustly defend any decision made in doing so,” the spokesperson said.