MI5 has raised alarm about a huge surge in the number of ‘high risk’ terror suspects after the threat to Britain moved up a gear.
A report has given a stark insight into the challenge facing the security services, revealing that they are devoting more resources to monitoring individuals who have received terrorist training or are plotting attacks.
It also highlighted fears about extremists driven out of Iraq and Syria and delivered a chilling assessment of ISIS’s murderous ambitions – with an arm of the group said to be plotting terrorism in the West ‘pretty much all day every day’.
The disclosures are contained in the annual report published by parliament’s Intelligence and Security Committee.
Police patrol the streets of Manchester following the deadly attack on the Arena in May
The committee’s report highlighted fears about extremists driven out of Iraq and Syria. Pictured are jihadis parading in Raqqa last year
Members are given access to highly classified material and take evidence from cabinet ministers and senior intelligence officials.
Committee chairman Dominic Grieve said: ‘The scale of the terrorist threat facing the UK is unprecedented in terms of the number of current investigations and the overall number of ‘individuals of interest’.
‘MI5 have told us that it represents a pace which they have not experienced before.’
MI5 described how ‘the most striking shift in the composition of CT (counter-terrorism) casework in the last five years was the proportion of what we refer to as high-risk casework’.
Typically, ‘high-risk casework’ refers to individuals who have received terrorist training or are attempting to procure the means to carry out an attack, but who may not yet have a current attack plan.
Previously, this sort of work represented a smaller share of MI5’s activity, with a greater proportion of work being ‘slower burn’ in character and requiring less resource-intensive monitoring, such as radicalisation or fundraising cases.
MI5 has about 3,000 ‘subjects of interest’ on its radar, on top of a larger pool of 20,000 individuals looked at as part of previous investigations.
The report said: ‘Keeping track of, assessing and applying proportionate investigative resources to such a large number of individuals is an extremely challenging task for the intelligence and security community.’
Efforts to contain the threat have come under close scrutiny this year following a flurry of attacks.
In addition to five terrorist incidents in London and Manchester this year, security agencies have foiled nine plots since the Westminster atrocity in March.
The committee also assessed the threat from so-called ‘foreign fighters’ who left Britain and other countries to take part in fighting alongside IS, which is also known as Daesh.
Since the start of the conflict in Syria, more than 850 UK-based individuals ‘of national security concern’ are thought to have travelled to the region.
It is thought about half of those have returned, more than 300 are believed to still be in Syria, and about 100 have been killed.
The report said: ‘As the territory of Daesh is squeezed by military action in Syria and Iraq, the dispersal of this group of foreign fighters becomes a serious concern, raising questions about when and where they will resurface, and what their intentions will be.’
MI5 said it was ‘very concerned’, adding: ‘A year from now most of them will not be in Syria and Iraq, probably. Who can say how this will unfold?’
The number of British children growing up inside the so-called Caliphate, educated and indoctrinated by IS, was identified as a further complication by the committee.
MI5 told members it was working with partner agencies to develop intelligence collection on the intent of the people driving terrorist planning from Syria and Iraq.
‘There is part of Daesh which is functionally best described as an external operations department which has a whole bunch of people which pretty much all day every day are plotting terrorism in the West in various countries in various ways,’ the agency said.
ISC chairman Dominic Grieve (pictured in the Commons last week) said the terror threat to Britain was at ‘unprecedented’ levels