The terrorist threat in the UK has become severe in the wake of the Vienna terrorist attack overnight and the wave of a series of violent incidents in France, the government said.
The decision of the independent Joint Terrorism Analysis Center (Jtac) means that the terrorist risk is back to its second highest level, meaning that an attack is deemed “highly probable” – whereas before it was simply judged ” likely”.
Jtac had unexpectedly lowered the level of the national threat to a substantial level last November, following the death of the leader of Isis, Abu Bakr al-Baghdadi; before that it was severe or even higher since August 2014.
In recent days, Islamist propagandists using social media have focused particularly on France, whose president, Emmanuel Macron, has vigorously defended the country’s secularism, following a series of attacks that began last month when a teacher was killed after showing caricatures of the Prophet Muhammad to students.
But the tipping point appears to have been Monday night’s attack in the Austrian capital, where five people, including an assailant, died in a country not known to be targets of Islamists. It is well established that terrorist attacks in one country encourage copiers elsewhere.
Intelligence agencies said earlier that the UK should be “especially vigilant” in the wake of the Vienna attack, especially as England is set to enter its own lockdown on Thursday.
Intelligence sources added that it was not clear at this point whether the attacks in Austria had been timed to coincide with the last night before a lockdown began, when more people than usual would have gone out in the evening and in the streets.
But it would be prudent to take that timing into account in the run-up to the start of the England-wide lockdown which is expected to begin just after midnight in the wee hours of Thursday.
Last month, new MI5 chief executive Ken McCallum said the security service had disrupted “27 late-stage terrorist plots in Britain”, the majority of which were Islamist extremists.
Jtac is based within MI5 but operates independently of MI5 and ministers. Its members are made up of all the intelligence agencies that speak out on the threat to the UK from all forms of terror.