More than a fifth of information passed by the public to police helps foil terrorist attacks, with 18 plots thwarted since March 2017, a counter-terror chief has said.
A record 700 terror investigations are ongoing, up from around 500 in 2017, assistant commissioner and head of UK counter-terrorism policing Neil Basu said.
Mr Basu said he was “incredibly grateful” that 2018 was spared the level of carnage of the previous year, when dozens of people were killed in attacks in London and Manchester.
However, he warned the “worst-case scenario” was public complacency, revealing that there had been a “dramatic” fall in the number of instances information was reported to the police.
More than 31,000 pieces of information were passed to police in 2017, which more than halved to 13,093 in 2018.
In both years, just over a fifth of the information passed on was “very significant”, meaning it directly led to the identification of a suspect or plot or was a small piece of the jigsaw that helped a plot be disrupted or criminal be prosecuted, Mr Basu said.
He added that part of the reason behind the fall could be the dominance of Brexit, which “undoubtedly” took up much attention last year, when there was very little terrorist activity compared with 2017.
Two continuing concerns were the potential of radicalised fighters returning from abroad and the spread of propaganda online, he said.
Drawn on the latter, Mr Basu said: “It’s not so much the volume of threat, but a shift in the threat to the young and the malleable, even the mentally ill who are being affected by what they are seeing, and they are taking that and then using very low-sophistication measures, things that everyone can get access to – a knife or a vehicle – and making an attack.
“And those are the kind of things that worry us most, they are the hardest to see and they are the hardest to stop.
“And that’s why we need communities to stand up and report changes in behaviour that they are seeing within their communities which might actually help us stop these things before they happen.”
He added: “If one in five times someone picks up a phone or emails us is a significant piece of intelligence, that is a major contribution from citizens and we want that to continue.”
Four far-right radical extremist plots and 14 Islamist terror plots were foiled by police and the security services within the last two years.
This compares with 30 planned attacks that were successfully disrupted in the four years prior to March 2017.
Mr Basu was speaking at the launch of a major cinema advert campaign to increase people’s awareness of suspicious activity and encourage them to report it to police.
The 60-second film shows a series of scenarios, such as a man stockpiling hazardous material and another buying weapons, before rewinding and zooming in on the danger.
An on-screen message reads: “Unfortunately life has no rewind button.
“If it doesn’t feel right, ACT.”
Asked why the advert was being shown in cinemas, Mr Basu said: “Well, the great thing about cinema is you’re here, you’re trapped in the audience and you’ve got to watch it.”
It will be shown at 120 cinemas across the UK over eight weeks from January 25.