As we approach the ruling on Shamima Begum's appeal against the removal of her citizenship, here's a reminder of how we got here.

Shamima Begum was a 15-year-old school girl when she left her home in Bethnal Green to travel to Syria. Born and raised in east London, Begum travelled to an IS stronghold in Raqqa, Syria, alongside two friends in 2015.

She is the best-known case among thousands of men, women and children who have been held in Syrian detention camps and prisons since the IS "caliphate" was defeated in 2019. Many come from countries that do not want them back.

The now 24-year-old had three children in Syria, all of whom died. In February 2019, Begum was found in a camp in north-eastern Syria. She had her British citizenship stripped on national security grounds by then- Home Secretary Sajid Javid.

Since then, Begum applied to enter the UK for a short time - but was refused the “leave to enter” permission.

At the Special Immigration Appeals Commission hearing in 2022, government lawyers said Shamima Begum joined the so-called Islamic State group "with her eyes open".

Her legal team argued she was trafficked to Syria for sexual exploitation, and her age at time - she was 15 years old - should be taken into consideration.

But Home Office lawyers told the tribunal: "The assessment made by the Security Service [MI5] was that [Begum's] travel was voluntary and demonstrated her determination and commitment to aligning with Isil (another name for IS, meaning "Islamic State in Iraq and the Levant").”

They went on: "She travelled for the purpose of aligning with Isil, and once in Syria she did in fact align with Isil.

"The assessment is that she did that with her eyes open. The ideology of Isil and their uncompromising brutality had been widely covered in the media."

Dominic Casciani
Home and legal correspondent

It was nine years ago last week that Shamima Begum went to Syria - and five years ago that she was deprived of her British citizenship.

The then-home secretary, Sajid Javid, took that decision after Begum had spoken to journalists who tracked her down in a camp following the collapse of the self-styled Islamic State.

In February 2020, a semi-secret court that reviews citizenship cases, ruled that Begum could lose her British passport because she could ask Bangladesh to make her a citizen.

A year later, the Supreme Court added to her woes, saying that the government was under no obligation to bring her back to the UK just because she could not take part in her own case.

That main case began in November 2022 - and her lawyers challenged the evidence that she was a threat to the nation. The government won again.

The BBC’s Josh Baker investigates the divisive story of Shamima Begum in an award-winning podcast series.

The Shamima Begum Story takes listeners inside Baker’s attempts to figure out what really happened to Begum, unearthing new information about one of the most talked about stories of our time.

He travels from Bethnal Green in east London to the depths of what was IS-controlled Syria, as he challenges Begum and investigates if the story she tells is true.

• You can listen to the investigative podcast series here.

As we've been reporting, the removal of Begum's British citizenship means she is now effectively stateless.

Under international law, a stateless person is someone who is "not considered as a national by any state under the operation of its law".

The Universal Declaration of Human Rights, external states that everyone has the right to a nationality and "no-one shall be arbitrarily deprived of their nationality".

But, the home secretary has the power, external to strip an individual of their British citizenship on the basis that it is "conducive to the public good", as long as the person would not become stateless as a result.

The Home Office says that the exception to this is where the UK government believes the person is eligible to acquire the citizenship of another country - even if they do not currently have dual nationality.

Begum, who is now 24 years old, still lives in the al-Roj detention camp in north-eastern Syria, where she will probably remain for the foreseeable future as she is effectively stateless.

Experts have said she could have claimed permanent Bangladeshi citizenship if she applied up until her 21 birthday, but didn’t - and Bangladesh's ministry of foreign affairs has said Begum is not a Bangladeshi citizen and there is "no question" of her being allowed into the country.

She has, for years now, said she wanted to come back to the UK.

Expert lawyers with experience in Bangladeshi citizenship cases have told the BBC that under Bangladesh law, a UK national like Begum, if born to a Bangladeshi parent, is automatically a Bangladeshi citizen.

That means that such a person would have dual nationality. If the person remains in the UK, their Bangladeshi citizenship remains in existence but dormant.

Under this "blood line" law, Bangladeshi nationality and citizenship lapse when a person reaches the age of 21, unless they make efforts to activate and retain it.

Begum was 19 years old when she was stripped of her UK citizenship, which likely - in part - gave Home Office lawyers and the home secretary reassurance there was a legal basis for stripping her of her UK citizenship.

The government has the power to remove someone's UK citizenship if it is "for the public good" and would not make them stateless; if the person obtained the citizenship through fraud; or if their actions could harm UK interests and they could claim citizenship elsewhere.

The power has been used against members of proscribed organisations such as al-Qaeda and IS, or those who obtained their British citizenship fraudulently.

The Nationality and Borders Act has made it easier for the home secretary, in certain circumstances, to remove citizenship without telling the person in question.

Such circumstances include national security concerns or if the individual has been prosecuted for a serious crime.

Dominic Casciani
Home and legal correspondent

The Court of Appeal is ruling whether a semi-secret court called the Special Immigration Appeals Commission (SIAC) got it right when it decided in February last year that Begum was fairly stripped of her citizenship.

That panel accepted that there were credible suspicions that Shamima Begum had been trafficked, as a 15-year-old, to Syria to become an Islamic State bride. A child could not consent to that fate and therefore, her lawyers said, she was a victim.

While SIAC made its concerns very clear, it cannot legally substitute its views for a minister’s decision - that’s not how the law works.

If the then-home secretary’s decision to strip Begum of citizenship in 2019 could be regarded as one that any reasonable person could have fairly reached, and also within his power, the court must let it stand.

Whoever wins, it feels a racing certainty that the losing side will try to take the case to the Supreme Court - for a second time.

Image source, Getty Images

Begum is one of three east London schoolgirls who travelled to Syria in 2015 to support the self-styled Islamic State.

She was 15 years old when she left. She left with her friends Kadiza Sultana and Amira Abase. Kadiza is thought to have died when a house was blown up, and the fate of Amira is unknown.

Begum was born in the UK to parents of Bangladeshi heritage but does not have Bangladeshi citizenship. Her British citizenship was stripped on national security grounds in 2019 when she was 19 years old, after she was found, nine months pregnant, in a Syrian refugee camp. The baby later died of pneumonia.

She has since appealed the decision and says she wants to come back to Britain.

Begum lived under IS rule for more than three years. She married a Dutch member of IS, who is currently held in a Kurdish detention centre, and lived in Raqqa, once a stronghold of the so-called caliphate. She had three children, all of whom have died.

Begum has admitted that she joined IS knowing it was a proscribed organisation. She has also said that she was “ashamed” to have joined the group and regrets it.

Nadia Ragozhina
Live reporter

Good morning and welcome to our live coverage of the Court of Appeal’s decision on Shamima Begum’s bid to overturn the removal of her British citizenship. It was revoked after she travelled to Syria in 2015 to support the group calling itself Islamic State (IS).

This is the second time that Begum has tried to have the government’s decision overturned.

Last February, Begum lost her first appeal. The Home Office argued Begum was a risk to national security in 2019, and the MI5 assesses she still poses a risk.

Stay with us as we’ll bring you the latest developments and analysis in this divisive case.