The official terror threat level for the UK has been raised from “substantial” to “severe” following a spate of attacks in Jewish neighbourhoods in recent weeks.
The upgrading in threat level means a terror attack is “highly likely”.
The Joint Terrorism Analysis Centre announced the decision on Thursday.
It comes after two Jewish men were stabbed in Golders Green on Wednesday, the latest in a number of attacks in Jewish neighbourhoods in recent weeks.
The suspect was named as Essa Suleiman, a 45-year-old British national born in Somalia who came to the UK legally as a child in the 1990s.
Here is how the threat level system works:
What does the severe rating mean?
That authorities believe an attack in the UK is “highly likely”.
How many levels are there?
Severe is the second highest out of five, behind critical, which means an attack is expected imminently. The other three levels are substantial (an attack is a strong possibility), moderate (an attack is possible but not likely), and low (an attack is unlikely).
Who decides the threat level?
A body called the Joint Terrorism Analysis Centre (JTAC), which was established in June 2003 and is based at MI5’s London headquarters.
The JTAC is comprised of representatives from 16 Government departments and agencies.
How is a judgment reached on the threat level?
A number of factors may be taken into account, including available intelligence, terrorist capability and terrorist intentions.
How has the threat changed over the years?
The level was first made public in 2006. Since then, it has most often been at the severe level, and not been lower than substantial.
The critical level has been in place four times over the 20-year period: in August 2006, following a plot to detonate explosives on transatlantic flights; June 2007 over an attempted car bomb attack at Glasgow Airport; and in May and September 2017 after the Manchester Arena bombing and the Parsons Green District line attack respectively.
The UK’s rating was downgraded to severe a few days after the Parsons Green incident and remained there until it was lowered to substantial in November 2019.
The last time the level was raised to severe was in November 2021 after two attacks in the space of a month, with a car explosion outside a Liverpool hospital on Remembrance Sunday and the murder of Conservative MP for Southend West Sir David Amess in October.
It was downgraded back to substantial in February 2022, where it has remained since.
How long does a threat level remain in place?
It depends on how high it gets. The threat level has only stayed at critical on each occasion for a matter of days and is usually downgraded once authorities have arrested suspects or are confident there is no immediate risk of another attack.
The JTAC reviews the terror level every six months but does not always raise it following attacks. It considered increasing the level to severe just weeks after the downgrading in November 2019 after the London Bridge Fishmongers’ Hall attack but kept it at substantial.

