article_snippet.sent: The number of Britons who have travelled to Iraq and Syria to join ISIS is twice than what has previously been reported.
article_snippet.sent: It is now thought that 1,600 Brits have joined ISIS, foreign intelligence officials told the Sunday Times. '
article_snippet.sent: We believe that 1,600 is a very conservative estimate and We're seeing at least about five people leaving the UK for Syria anbd Iraq every week - and that's not to count the ones We don't know about,' an intelligence official said.
article_snippet.sent: According to the newspaper, about 500 have returned to the UK after heading to the Islamic State.