The UK’s terror threat level has been lowered to substantial, meaning that further attacks are deemed “likely” rather than “highly likely”.
The home secretary, Priti Patel, said: “The decision to lower the threat level from severe to substantial is due to the significant reduction in the momentum of attacks in Europe since those seen between September and November 2020.
“However, the UK national threat level is kept under constant review and is subject to change at any time.”
In a statement to parliament, Ms Patel said there was still a high level of threat and that the public should remain vigilant.
The decision was taken by the Joint Terrorism Analysis Centre (Jtac), which conducts formal reviews every six months based on intelligence and risk factors.
They are among 12 such attacks to have taken place in the UK since March 2017 – 10 Islamist and two far-right.
Speaking to The Independent in December, the head of UK counterterrorism policing said the threat level was raised in November because terror attacks had hit France and Austria on the eve of national lockdowns, and there were fears that extremists would take their “last opportunity before the streets were cleared” with incoming restrictions in England.
Assistant Commissioner Neil Basu said the coronavirus pandemic had put a “different spin” on potential terrorist targets, with iconic locations and normally crowded places standing empty.
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“The Streatham attack proved that it’s not necessarily the iconic Oxford Street locations or the big crowded spaces that we need to worry about; we need to worry about terrorists being prepared to commit an atrocity anywhere,” he said.
“My biggest concern is the growth of online radicalisation, which has allowed conspiracy theories and existing Islamist and extreme right-wing terrorism, and all kinds of other single-issue terrorism, to thrive 24/7 internationally at the speed it takes to press a button.
“That is incredibly worrying, and if you add that mechanism to people’s grievance, their isolation which has been compounded by Covid, and individuals who may have complex psychological needs or even mental illness, that is a perfect storm.”
Isis, al-Qaeda and other jihadi groups have continued to call for supporters around the world to commit atrocities.
Security services are also monitoring the rising threat from far-right groups that encourage lone-actor terror attacks.