Police made the highest number of terrorism-related arrests since 2019 last year, an 11 per cent increase year-on-year.
Official figures showed there were 248 terror-related arrests in all during 2024, 25 more than in the previous 12 months.
However, the total was still significantly below the peak of 467 in 2017.
Counter-terrorism police said the latest increase reflected rising perils to the UK from ‘state threats’ posed by countries such as Russia, China and Iran.
Last year’s anti-terrorism arrests led to 84 people being charged – either with terrorism or another type of offence – down from 109 the previous year. The record was set in 2017 with 181 individuals charged.
Senior national co-ordinator for counter-terrorism policing, Deputy Assistant Commissioner Vicki Evans, said: ‘The ripples of global uncertainty continue to be felt domestically and that is reflected in number of arrests our officers made last year.
‘We have also been clear that our demand has increased when it comes to investigating and disrupting national security related cases – those linked to state threats.’
In October Sir Ken McCallum, director general of the Security Service, MI5, warned there had been 20 ‘potentially lethal’ Iran-backed plots in Britain over the previous two years.
Counter-terrorism police said the latest increase reflected rising perils to the UK from ‘state threats’ posed by countries such as Russia, China and Iran. Pictured: Police officers outside a house on Walton Drive in High Wycombe, Buckinghamshire, after a massive security operation resulted in arrests across the UK in connection with an alleged plot to blow up passenger jets leaving UK airports for the US (2006)
An armed police officer guards the outside of the Royal London Hospital in Whitechapel, east London, where a 23-year-old man shot during an anti-terror raid was believed to have been taken
MI5 investigations into state threats jumped by 48 per cent last year, he added.
A counter-terrorism policing spokesman said more than a fifth of its casework now focuses on protecting the UK against state threats.
DAC Evans added: ‘For the last 18 months, counter-terrorism policing has been operating at a very high operational tempo and it is no surprise to see our teams arrested well over 200 people last year.
‘Within those arrests are three late-stage attacks that were disrupted thanks to the actions of our officers and our partners in the security service.
‘Day in day out, our officers and staff are working with partners to help keep the public safe and today’s figures demonstrate the scale of work we’re undertaking.’
Significantly, there was a small fall in the number of children being arrested under counter-terrorism powers, after a surge over the previous four years.
During 2024 there were 39 under-18s were held by police using anti-terror powers.
It was down four on the previous 12 months – but still the second-highest annual total since records began in 2002.
Anti-terror police stand outside a house in Northern Road, Aylesbury, Thursday July 14, 2005 which they raided in connection with the London “burning cross” bombing gang
MI5 buildings in London. The services’ investigations into state threats jumped by 48 per cent last year
Of those arrested, three were charged – compared to 16 the previous year.
DAC Evans said: ‘While the data shows a slight dip in arrests of young people, our teams still arrested a concerning number of young people last year.
‘The offences of those who were arrested range from suspicion of possessing a firearm, to those who have allegedly shared terrorist material online, and to those who were thought to be preparing acts of terrorism.
‘For over five years now counter-terrorism policing has been warning about the number of children and young people in our casework and investigations.
‘And while this trend cannot be reversed by law enforcement alone, we must continue to work with our partners to stop young people, no matter their age, from causing harm to the public.’
There were 32 arrests of people in the 18 to 20 age group, up six year-on-year; 25 of those aged 21 to 24; 31 of those aged 25 to 29; and 121 in the over 30 bracket.