Jonathan Russell is head of policy at Quilliam , a counter-extremism think tank in London. Joshua Stewart is a strategic communications officer there. The opinions in this article belong to the authors.

(CNN) Wednesday's attack on London was expected, planned for, and in the view of many, a long time coming.

The UK terror threat has stood at "severe" for more than two years now, meaning that the response to this kind of attack in such a high-profile location had been extensively rehearsed.

This was amply reflected in the way in which London, its security services and the public responded: rapid first responders, clear public information dissemination and a narrative of resistance

In many ways, we could not have hoped for a more effective response -- from both the police and members of the public.

Such full-spectrum, whole-of-society reactions are the only way to mitigate and dilute the effect of unsophisticated, "lone wolf" acts of terror.

Equally, the elasticity with which the police were able to absorb the shock of attack, contain the threat and then coordinate simultaneous raids across the country on known suspects -- without causing substantial fear or disruption to public life -- is remarkable.

Despite this, there is, of course, room for us to assess the current security and intelligence picture; evaluate our strengths, limitations and what we can learn from this.

"He was not part of our current intelligence picture," British Prime Minister Theresa May read Thursday morning to a reconvened Parliament.

From this language, it is possible that the attacker had proactively gone "dormant" in his overt extremist activities, so as to reduce the "threat to life" assessments from security services -- meaning they would turn their attention and resources elsewhere.

At this stage, it is hard to say whether this was deliberate. If so, then it is extremely likely that other would-be attackers will be doing exactly the same thing.

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In the UK, there are an estimated 3,000 to 4,000 "violent Islamist" extremists leading to hundreds of "live" counterterrorism investigations at any one time.

Digital and signals intelligence can only go so far. To carry out human surveillance on just one target requires several human officers.

In short, prioritization is essential. This is where "lone wolf" terrorists, who usually operate outside of a command and control pattern, become immensely difficult to stop: The more sophisticated and preplanned the plot, the more likely security services can detect, deter and disrupt.

Terrorists always look for the path of least resistance. This is why they fill post-conflict vacuums. But it is also why we have seen a proliferation of unsophisticated attacks in Europe. Trucks in Nice, France, and Berlin, cars and knives in London. Security services simply cannot prevent these in all cases.

So where does this leave us? However tempting it is, we should avoid hinging our response around hard security measures. Counterintuitively, our best way of responding is to innovate and enhance our soft power and preventative approaches, so that would-be lone actors become less likely to slip through the net of society.

Counter-extremism initiatives fill this gap. If extremist recruiters seek to manipulate grievances, teachers and youth workers must develop programs to address them through promoting democratic responses.

As radicalizers identify the vulnerable experiencing identity crises and promote a ready-made group identity as a quick fix, we must proactively show them alternative pathways, preventing these people from becoming radicalized.

Because ISIS promotes its fantasies so effectively online, we must enlist communications firms and social media experts to counter such narratives -- and moderate imams to challenge their pernicious Islamist ideology while also distinguishing it from Islam.

It is incumbent on all parts of civil society to support this common cause to prevent terrorism. First responders and the security services do a wonderful job, but there are simply some things they cannot do alone.