The so-called Islamic State group may be planning a “spectacular” attack in the UK, the national head of counter-terrorism policing warns.
Assistant Commissioner Mark Rowley said there was evidence IS was “trying to build bigger attacks” globally, and the UK was among its targets.
He said IS had expanded its ambitions from smaller-scale targets to attacks on “Western lifestyle”.
However, he would not be drawn on any specific plans or operations.
Several attacks, including last year’s gun and bomb attacks in Paris, were inspired by IS, also known as Daesh.
Speaking at a briefing in London, Mr Rowley revealed the number of terrorism-related arrests in Britain hit record levels last year.
There were 339 arrests in England, Wales and Scotland – the highest yearly figure.
Scotland Yard – which published the data – said there had been a 57% increase in the last three years compared with the previous three.
The UK’s terror threat level is currently rated as “severe”.
This means that security and intelligence chiefs have concluded that a terrorism-related attack is highly likely.
Mr Rowley said in the past few years, IS had called on would-be jihadists to attack police and the military.
“In recent months we’ve seen a broadening of that – much more plans to attack Western lifestyle, and obviously the Paris attacks in November,” he said.
“Going from that narrow focus on police and military as symbols of the state to something much broader.
“And you see a terrorist group which has big ambitions for enormous and spectacular attacks – not just the types that we’ve seen foiled to date.”
IS is trying to get supporters who have received military training in Syria into northern Europe to stage attacks, he added.
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