The Reading stabbings are a reminder that terrorism is like a virus – we can only seek to mitigate the risk of attacks

When it comes to managing public risk, what remains constant is the need for vigilance and collective action

For the past four months we have become used to the idea that the best way to defeat a threat to public health is through a combination of science and collective effort. If we all work together we will win the war against coronavirus.

But the horrific stabbings in Reading serve as an abrupt and grim reminder that we can only ever hope to mitigate the risk of random attacks in public places.

Like a virus, terrorism can take many different forms but there is no vaccine to protect us against violence triggered by extremist ideology or motiveless attacks brought on by other factors such as mental health issues.

Deaths caused by terrorism may be statistically insignificant when compared to the 42,000 people who have already been taken by Covid-19, but each terror attack has a disproportionate impact on the public psyche.

From the IRA bombings of the 1970s and 1980s to the attacks on London’s transport system in 2005 right up to the current threat posed by Isis, we have had to accept the inherent everyday risk of random attacks against the public from groups rooted in political and extremist ideologies. Indeed, the war on terror looks no closer to being won than it did when it was first declared after the 9/11 attacks on America in 2001.

Yet successive governments in the UK have diverted huge resources to funding a raft of counterterrorism measures. The intelligence and security agencies, charged with combating terrorism, have an annual budget of £2.6bn, which has been increasing year on year.

Scotland Yard’s counterterrorism command, MI5 and GCHQ share a database of 40,000 subjects of interest. Of these, they have prioritised 3,000 who they believe pose the greatest threat. Under MI5’s traffic-light system, a further 500 are given the highest priority and are being investigated as part of ongoing counterterrorism operations.

There are people who may have, from time to time, expressed extremist views, which in turn have led to referrals to the Prevent programme or the anti-terror hotline. Some referrals may include reports of an individual’s support on social media for a caliphate or a state governed by a doctrine of white supremacy.

The security services and Prevent teams are inundated with these kinds of referrals, all of which must be investigated. At the same time, police and MI5 officers are already committed to hundreds of counterterror investigations and inquiries. MI5 must try to assess which of the thousands of cases matching the government’s fluid definition of extremism deserve resources.

Given this morass of data and investigation, it is no wonder that individuals, like the London Bridge and Westminster Bridge attackers, who appeared in the peripheral vision of the security services, still manage to slip through the net.

For years the security services have been employing teams of behavioural scientists to help them understand the terrorist mind so they can make the right decisions. Now the government has recruited spooks to help tackle Covid-19. Last month the government established a Joint Biosecurity Centre, responsible for setting coronavirus threat levels. Until last week it was led by Tom Hurd, the director-general of the Office for Security and Counter-Terrorism who has been tipped to be the new head of MI6.

It seems in the world of public risk mitigation, the line between science and surveillance is becoming more and more blurred. But what remains constant is the need for vigilance and collective action.