Anti-terror arrests surged to a new record high as Britain was hit by a wave of attacks amid a “step-change” in the momentum of the threat.
In the year to the end of March 2018, a total of 441 individuals were held as part of terrorism investigations – a rate of well over one a day.
This was the highest number of arrests in a year since data collection started in 2001, and an increase of 17% compared with the previous year.
The uptick was partly driven by police operations following the five attacks in London and Manchester between March and September last year. In total, 52 arrests were made after the incidents.
It also emerged that the total number of arrests linked to suspected terrorism-related activity in Britain since the 9/11 attacks in 2001 has now passed the 4,000 mark, standing at 4,182 as of the end of March.
Metropolitan Police Assistant Commissioner Neil Basu, the national policing lead for counter-terrorism, said: “With the terrorist attacks of 2017 we saw a genuine step-change in momentum.
“As a result, our operational activity increased to meet the new and emerging threats we now face.
“A year on and our activity continues to be at unprecedented levels; shown, not least, by the fact that, in the past year, working together with the security services we have stopped an average of one terrorist attack every month.
“Police, together with the security services are determined to make the UK as hostile an environment for terrorists as possible.”
In the latest Home Office figures, the scope of data collection has now been widened to include all arrests with a “terrorist element”, whether or not the suspected offence was terrorism-related or not.
This means that for the first time the national totals include cases known as “disruption” arrests. This is where someone who police believe may be linked to terrorist activity is held in relation to other suspected criminal matters such as fraud, robbery or drugs offences.
Mr Basu said: “We’re taking every possible opportunity to disrupt terrorist activity – be it making arrests for terrorism offences, or for other types of criminality that the individuals or groups are involved in.”
Of the 441 arrests: 143 (32%) resulted in a charge, of which 114 were charged with terrorism-related offences; 250 (57%) were released without charge; 27 (6%) were released on bail pending further investigation; 20 (5%) faced “alternative action” such as a caution or being transferred to immigration authorities; and one case was pending as of the middle of April.
Fifty-six of those held were females, the highest number arrested in a financial year since data collection started.
There were increases across nearly all age groups compared with the previous year, with a record 27 arrests of under-18s.
Arrests of people of Asian (180) and white (151) appearance were up by 11% and 10% year-on-year respectively, with both at the highest level recorded in a financial year.
The figures showed that 320 of the arrests were recorded in the international category, which covers suspected activity linked to or motivated by terrorist groups based outside the UK – such as Islamic State.
Seventy-four were logged in the domestic bracket, which relates to cases where there is no connection to either Northern-Ireland related or international terrorism. Further breakdowns are not given but this section would include arrests relating to suspected far-right activity.
As of the end of March, 228 prisoners were in custody after being charged with or convicted of terrorism-related offences.
The scale of the terror threat is seen as unprecedented.
MI5 and police are handling at least 500 live investigations involving roughly 3,000 individuals, while there is a further pool of more than 20,000 former “subjects of interest” who must be kept under review.
Counter-terror agencies say they have foiled 12 Islamist and four extreme right-wing plots since March last year.