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."
There were increases across nearly all age groups compared with the previous year, with a record 27 arrests of under-18s.
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.
As of the end of March, 228 prisoners were in custody after being charged with or convicted of terrorism-related offences.
Counter-terror agencies say they have foiled 12 Islamist and four extreme right-wing plots since March last year.