Was it the right decision? A UK court has ruled that Shamima Begum, who left Britain to join a terrorist group, cannot return to the country of her birth. Critics say this is bad news for thousands of other citizens.
ISIS bride loses UK citizenship, judge rules
Glossary
Turkey - Officially the Republic of Türkiye, a country that lies partly in Europe and partly in Asia at the east of the Mediterranean.
Syria - A Middle Eastern country that was the site of much of the fighting during the Crusades.
Islamic State - A terrorist organisation that captured whole swathes of territory in Iraq and Syria in 2014, and launched a series of attacks in Europe and North America. It is also known as ISIS or ISIL.
Home secretary - In Britain, they are responsible for national security, immigration and policing.
Groomed - When someone forms a relationship with a vulnerable person, especially a child, with the intention of later exploiting them.