A British-born woman who traveled to Syria in 2015 to join the so-called "Islamic State" (IS) terror group, and then had her British nationality stripped, on Wednesday lost an appeal to have her citizenship reinstated, on the grounds of national security.

What did the tribunal decide?

The Special Immigration Appeals Commission ruled that there was a "credible suspicion" that Shamima Begum was trafficked to Syria for the purposes of "sexual exploitation" but that the suspicion was insufficient for her appeal to succeed.

The tribunal said there also were "arguable breaches of duty'' on the part of state bodies in allowing her to travel to Syria.

However, Judge Robert Jay said that since she remains in Syria, UK authorities were not obliged to facilitate her return.

A UK Home Office spokesman welcomed the ruling and said, "The government's priority remains maintaining the safety and security of the UK and we will robustly defend any decision made in doing so."

Begum's lawyers indicated that they would challenge the court's decision.

In November, her legal team argued that Britain's Home Office failed to investigate whether she was a "child victim of trafficking."

Who is Shamima Begum?

In 2015, Begum — who is now 23 years old — traveled to Syria when she was 15, along with two other girls from London, to marry IS fighters.

Thousands of fighters from all over the world, swelled the terror group's ranks, with many renouncing their nationalities and opting to remain in the self-styled caliphate the terror group established in the territory it controlled at the time.

However, when IS was defeated in 2019, and thousands of its fighters and families were captured, the challenge of what to do with them emerged. Many, like Begum, remain in camps in northern Syria.

In the same year, then-Home Secretary Sajid Javid, decided to revoke her citizenship after she was found in the Al Hol detention camp in Syria. Begum had given birth to three children, all of whom died.

Begum and others in her position, have been the source of debate as to what to do with people of various nationalities who joined the terror group when it was capturing vast swathes of territory in northern Syria and Iraq.

kb/sms (Reuters, AP, AFP)