EU counter-terror chief: UK home to 35 000 radical Islamic extremists

De Kerchoce told Spain’s El Mundo newspaper that Europe should brace itself for more terror attacks like seen in Barcelona and Cambrils.

“We are going to suffer more attacks,” he said as he pointed out that the UK has more radicalised muslims than any other country in Europe.

“The majority, except Brussels and Paris, were not directed from Raqqa but inspired, and then ISIS claimed responsibility,” he said, referring to the Syrian city once considered the de facto capital of the terrorist group.

“The group’s propaganda no longer calls so much for people to travel to the ‘caliphate’, but to launch attacks in their places of origin or of residence, even on a small scale with homemade weapons,” he explained.

“The United Kingdom has identified 20,000 to 35,000 radicals. Of these, 3 000 are worrying for MI5, and of those 500 are under constant and special attention,” he said.

By comparison other European countries, including France, have far fewer radicals. “France has 17 000. Spain many less, but more than 5 000 I suppose. In Belgium almost 500 have been to Syria and there are around 2 000 radicals or more.”

But De Kerchove said he could not exactly say how many were present in Europe as a whole. “I wouldn’t like to put a concrete figure on it, but (in Europe) tens of thousands, more than 50 000.

“We must select those who are really worrying and the most dangerous, and they should be monitored 24 hours a day, seven days a week.”

The counter-terrorism official warned that radicals were increasingly applying the islamic concept of “taqiyya” which means concealing their religious beliefs from those around them – in order to prevent early detection.

Police in Catalonia had been warned about Abdelbaki Es Satty, the alleged leader of the Barcelona cell, by counterparts in Belgium, but failed to react because they believed he presented no danger.

The official noted that no case of cyberterrorism has been recorded yet, “in the sense of penetrating or intending to penetrate the systems of nuclear power stations, prisons, electrical stations or aerospace”.

But he warned: “I would not be surprised if in the next five years it happens. Not that it works but that they try. One should not underestimate the potential of Islamic State.

“At the moment they don’t have the knowledge for this. But in the dark net you can find system vulnerabilities for sale.” He added that they had the money to pay for hackers to penetrate such systems.

According to De Kerchove European security services had “dismantled cells, destroyed plans, arrested people. Spain has arrested 51 jihadis so far this year. In 2016, 69, in 2015, 75.”

He said the problem would not be solved any time soon. “This is a generational problem. It will take time, decades, it won’t be resolved in months.”