Nearly 400 of the 800 Britons who travelled to Syria since the start of the conflict there have returned, while the passports of 24 people intending to travel for terrorism-related activity have been removed, home secretary Theresa May has said. Refusing to comment on the latest Islamic State video or on individuals it features, May told parliament on Tuesday that it was a “barbaric and appalling video” in which the group sought to intimidate and spread hateful propaganda, “but in doing so they only expose their own depravity and the emptiness of their proposition”. May told the House of Commons: “Since the start of the conflict in Syria, more than 800 people from the UK who are of national security concern are thought to have travelled to the region, and we believe that around half of those have returned. Those who have travelled include young women and families.” Detailing legislative and executive action in view of the IS threat, May said in 2014, she had removed 24 passports from people intending to travel for terrorism-related activity. Since April last year, she said, exit checks were in place for all international commercial scheduled air, sea and rail services using Britain. “The UK has joined the European watch-list system – so-called SIS II – meaning we are now alerted when any individual is stopped at a border checkpoint or by police anywhere in Europe and is checked against the system,” she said, according to the Hindustan Times.