Police: We have foiled seven ‘late-stage’ terror attacks since start of pandemic

The latest figures take the total number of foiled terrorism plots in the UK in the last four years to 32, Counter Terrorism Policing (CTP) said.

It comes as senior police officers warned the public “not to let their guard slip during the festive period”.

Since March 2017, there have been 18 disrupted plots related to Islamist extremism, 12 linked to extreme right-wing terrorism and two to left, anarchist or “single issue terrorism”.

Deputy Assistant Commissioner Dean Haydon, the senior national co-ordinator for CTP, said the public would be “well aware of the fact that the UK has suffered two terror attacks in quick succession, with the national threat level raising to severe – meaning an attack is highly likely.”

He added: “All of this combines to paint a picture of a sustained and high tempo threat, which our world-class police, security and intelligence services are doing everything in their power to combat.

“But it takes a whole society approach to effectively tackle terrorism, and co-operation between the police and the public is vital, so we need you to be vigilant, and we need you to be alert.

“As we approach the festive period, we need the public to help play their part in protecting the UK.”

He urged people to trust their “instincts” and contact police over suspicious activity.

Mr Haydon also expressed concern that children were “becoming an increasing proportion of our arrests”, in light of Home Office figures published on Thursday.

He added: “But it doesn’t have to be this way. Ideally we would identify when a young person is being led down the path towards terrorism activity and use the Prevent programme to try and put them on a different path.”

He urged parents and other relatives to seek support if they feared a loved one might be following a “dangerous path towards extremism”.

Despite an overall drop in arrests, largely due to a fall in crime amid lockdown restrictions, 25 children were detained over terror crimes in the year to September.

This was the highest proportion recorded in a 12-month period, accounting for 13% of all arrests.

It was an increase of eight, up from 17 (8%) the previous year.

But the report said it was “largely a result of falls in arrests of those in older age groups”.

Earlier this year, the boss of MI5 revealed that agents were investigating teenagers as young as 13.

The threat of extreme right-wing terrorism had “grown and morphed quite substantially over the last five to 10 years”, with a “high prevalence of teenagers”, and tackling it needed “new expertise, new sources, new methods”, director general Ken McCallum said.

Although suggesting some youngsters could be “swept up with this toxic ideology for a period” due to its huge presence online, he warned: “It is already the case that in quite a range of our investigations, we do sadly see teenagers, minors, under the age of 18, some under the age of 16, presenting sharp risk.”