There’s been a surge in the number of arrests of British citizens accused of returning from the battlefields of Syria to take part in jihad, or holy war. British authorities fear the increasing numbers pose a domestic security threat. The threat is being taken seriously across the continent, with thousands of Europeans thought to be fighting in Syria.
Among the many thousands of amateur videos that have emerged from the Syrian conflict, one has stirred growing concerns among British security services.
It purports to show British citizen Abdul Waheed Majeed outside Aleppo, Syria earlier this month. He is surrounded by fighters from the Islamist rebel group Al Nusra Front - affiliated with al-Qaida.
When asked questions by Arabic-speaking fellow rebels, Majeed responds in a clear British accent.
"I can't speak. Everyone asks me. I'm not a very good speaker. My tongue got like a knot in it. I can't speak. It should come from the heart. I can't do it," said Majeed.
Majeed is then seen driving an armor-plated truck packed with explosives up to the walls of Aleppo prison.
Majeed and scores of others are killed; Syrian rebels reported that several prisoners escaped.
“The suicide bombing suggests a level of zealotry that is quite unprecedented. They are fighters, and they are on the ground to do two things: one is to remove Assad, but also to achieve martyrdom,” said Shiraz Maher, from the International Center for the Study of Radicalization at Kings College London.
Maher estimates there are between 200 and 366 British citizens fighting in Syria - more than went out to fight Jihad in Iraq or Afghanistan.
“Given the narrative of the Western world that our own governments regard Assad as a tyrant and someone who should be removed from power, it isn’t so morally ambiguous,” said Maher.
The British government is cracking down. In January alone, 16 Britons were arrested on their return home, suspected of taking part in the fighting or of attempting to travel there. For the whole of 2013, there were 24 arrests.
Past experience suggests the British jihadists pose twin security risks, said Rafaello Pantucci of the Royal United Services Institute.
“In Afghanistan and Pakistan, where we saw young Britons who were drawn out there to fight in some of the Jihad conflicts, ended up being directed by al-Qaida core to come back and launch attacks in the UK. In other examples like in Iraq, that young Britons were drawn out there, some of whom came back… and decided that it was their duty to try to do something in the United Kingdom,” said Pantucci.
The problem isn’t confined to Britain. Another suicide attack in December was reported to have been carried out by Nicholas Bons, a French jihadist fighting with the group the Islamic State in Iraq and the Levant.
It’s estimated that up to 700 French citizens have travelled to Syria. French anti-terror judge Marc Trevidic said there needs to be more engagement with Muslim communities at home.
“So far, we have only relied on anti-terrorist justice, this means on crackdown only, and that's a failure,” said Trevidic.
Anti-terror experts say social media allows would-be foreign jihadists to watch the Syrian conflict unfold in real time - and easily connect with fighters on the ground to plan their journey.