Activity by counter-terror police is at its highest level for nearly ten years due to fears that Islamic State sympathisers will launch attacks in the UK.
The Times reports that police are increasing armed patrols and are searching homes and cars, while also monitoring extremists who have returned from fighting in Syria.
The stepping up of security comes after the release of a video showing an unmasked British jihadist urging “all brothers in the UK” to seek revenge for British air strikes against the self-proclamed Islamic State.
Addressing Muslims who cannot make the journey to Syria and Iraq, the militant says: “Unlike us, you are blessed in that you can cause terror in the hearts of the kufar [non-believers], right in the centre.”
“You can cause terror right from within,” he adds.