The terrorist attack that left at least two people dead in Strasbourg on Tuesday night is a grim reminder of the high risk Europe continues to face from violent extremists. French police were searching yesterday for a 29-year-old man suspected of carrying out the shootings at the city's Christmas market. The man, an Islamist who was reportedly radicalised in prison, was on an intelligence services watch list as a potential security risk.
A recent decline in the number of terrorist attacks in Europe, combined with the battlefield defeat of Islamic State in Syria and Iraq, might have led some to conclude that the era of atrocities that began with the 2015 Charlie Hebdo killings in Paris and included attacks in Brussels, Berlin, Barcelona and London, had come to an end. There has been no attack resulting in more than 10 deaths since the summer of 2017, and jihadist attacks are down by more than 60 per cent since last year.
It's true that European states have made themselves less vulnerable. The rout of Islamic State has reduced the network's operational capacity. Security services have also succeeded in foiling big attacks – most recently in the Netherlands in September, when police arrested seven men over an alleged plot involving guns and explosives.
The continent faces a significant threat from trained jihadis returning from Syria and Iraq, but security experts believe a greater challenge is posed by homegrown terrorists, who have no direct link with IS or al-Qaeda but are inspired by their ideologies. The scale of radicalisation is huge: in France, some 26,000 individuals suspected of posing a security risk are on the same "S File" as the Strasbourg suspect, while, according to the EU, 25,000 Islamist extremists live in the UK, of whom 3,000 are deemed a threat.
The nub of the challenge is identifying what Gilles de Kerchove, the EU’s counter-terrorism coordinator, calls “the tipping point” – the moment at which someone with radical thoughts begins to prepare an attack. In some cases, the authorities succeed. In others, as we saw in Strasbourg, they are one step behind.