Saturday night's terrorist attack at London Bridge has left many calling for a solution to the problem of extremism. Some have even proposed internment.
But does internment ever work, or does it just make things worse?
Professor Eunan O'Halpin, Director of the Trinity Centre for Contemporary Irish History, defines internment as "the forced and indefinite detention of somebody against their will, without trial."
He explained our own history of internment, which has included Northern Ireland in the 1970s. While there is "no clear figure", thousands of people were interned during this period.
Eunan says that the effectiveness of internment is not clear cut.
"We don't have to like it, but we have to acknowledge the practical consequences. We can't say in Irish history that internment has never worked, any more than we can say that hunger striking always works. It's not that simple."
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