Children and teenagers are being recruited to terrorist organisations during lockdown in “worrying” numbers, according to Dominic Raab.

Updating MPs about so-called Islamic State (IS), also known as Daesh, the Foreign Secretary said the UK is tackling the group’s propaganda “head on”.

But he warned the terror group is “still able to carry out lethal attacks” and it remains the UK’s “most significant terrorist threat” both at home and abroad.

Speaking in the Commons Mr Raab said: “This is a critical moment.

“Yes, Daesh’s brand has weakened – it remains, nonetheless, globally recognised.

“In December 2020, the UK Counter-Terrorism Referral Unit saw a 7% rise in the volume of terrorist content online and we can see a worrying rise in the proportion of children and teenagers that are now being arrested for terrorism offences.

“And it was Assistant Commissioner Neil Basu of the Met (Metropolitan Police) who described lockdown and the accessibility of terrorist content online as a perfect storm because terrorists have digital access to those who are probably the most susceptible to extremist narratives.

“So we are tackling Daesh’s propaganda head on and I am proud the FCDO (Foreign, Commonwealth and Development Office) leads on this work on behalf of the global coalition.”

He added the UK Government has “carried out a range of targeted and effective cyber operations”.

On the threat posed by IS, Mr Raab said: “The safety and the security of our citizens is obviously the Government’s highest priority, it is at the core of our work in tackling Daesh, which remains our most significant terrorist threat – both at home and abroad.”

Mr Raab told MPs the Global Coalition Against Daesh estimates there are still “around 10,000 Daesh members at large across Syria and Iraq”, adding: “So support for Daesh still lingers on in many communities.

“At the same time, while Iraq and Syria remain Daesh’s primary focus, it also presents a clear and growing global threat.

“So diminishing Daesh’s ability to operate in other parts of the world, including Africa and Asia, must also be a priority for the international community. We must not allow it to take roots elsewhere.

“I can report to the House that on 11 February a coalition surveillance aircraft located a number of Daesh fighters – they were occupying two dispersed encampments on the banks of the Tharthar River, west of the city of Bayji (Iraq).

“Two UK Typhoon FGR4s conducted careful checks of the surrounding area for civilians before carrying out simultaneous attacks using two Paveway IV guided bombs against each group. The bombs hit their targets within the encampments, eliminating the terrorist threat.”

Mr Raab’s comments came as it was announced that police and UK intelligence services have foiled three terror attacks since the beginning of the coronavirus pandemic.

Counter Terrorism Policing disclosed the information as Home Office figures showed the number of arrests for terrorism-related activity fell by 34% in 2020, the lowest level in nine years.

Despite this, the number of terror plots prevented has risen to 28 since March 2017, police said.

For Labour, shadow foreign secretary Lisa Nandy said: “I was deeply troubled to hear the Foreign Secretary outline the way that children are being targeted by Daesh propaganda.

“Does (Mr Raab) agree that it is appalling that British children in the UK are being groomed to join Daesh? And can he therefore tell me what steps the Government is taking to protect children from this threat?”

Mr Raab advised people against travelling to Syria, adding: “We continue to work with all of those concerned to facilitate the return of unaccompanied or orphaned children where that’s feasible, where that can be done where there’s no risk to security and where practically it can be done.

“I won’t comment on the numbers, it’s obviously very sensitive but I take that very seriously. We regard those children as the innocents of the scourge of war and wherever it’s safe and possible, we will put our protective arms around them.”