West faces challenge in tackling threat of home-grown jihadis

Governments have every reason to worry about citizens going to Syria and Iraq to fight alongside Muslim jihadis of the group calling itself Islamic State. Should they return home, they will be battle-hardened and perhaps eager to carry out terrorist attacks. Their extremist ideology may radicalise others. British Prime Minister David Cameron rightly wants to deter Britons from joining the war and stop those with blood on their hands from coming back.

Under Cameron's proposals, airlines would have to hand over passenger lists to authorities and police would be able to confiscate passports. Ways are being looked at to keep out Britons who have joined Islamic State, perhaps even removing their citizenship. European countries have yet to consider such restrictions, allowing nationals to freely move to and from the conflict zone. The US is already cracking down on those suspected of wanting to take part, while Australia is also considering tough action.

About 3,000 of the 12,000 fighters who have joined Islamic State's battle for a global caliphate governed by strict sharia law are believed to be from Western nations. The appearance of a hooded man with a British accent in the videos in which American journalists James Foley and Steven Sotloff were beheaded has highlighted how deeply Britain is involved; the biggest groups of Western fighters are Britons and French. They have joined Islamic State for a number of reasons, among them searching for a Muslim identity and dissatisfaction with home. Enticed by the idealism portrayed on recruiting websites and having little difficulty in making their way to Islamic State's base in northern Syria, they are soon absorbed in the group's barbarity and radical ideology.

Governments have to prevent terrorism and the spread of extremism; clamping down on recruiting websites is the best place to start. But care has to be taken to not trample on civil liberties. Not all those who return from Syria and Iraq will have committed atrocities, nor want to continue fighting.