The events around RAF Fairford offer a timely reminder of a less visible part of Britain’s counter-terrorism system: the role of the public. In the early hours of September 27, armed officers responded to a report of suspicious vehicles near the base and arrested five men. A local farmer had found a road blocked late at night as she returned home and raised the alarm.

The men, all in their 20s and UK nationals from London, were detained under the Explosives Act and on suspicion of preparing a terrorist act. They have now been released on police bail while the investigation continues. Police have said several lines of inquiry remain open, and it later emerged that one of the arrested men also made a 999 call in the early hours of September 27.

The Gloucestershire airbase is owned by the Ministry of Defence, but operated by the US air force under a special agreement.

There is another story here that is worth examining. Gloucestershire Police thanked the public for their assistance and said they remain its “eyes and ears”. But what does this actually mean in terms of counter-terrorism?

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Counter-terrorism does not operate solely through intelligence agencies and specialist police units. Information can originate with people going about their everyday lives. This could be local residents, teachers, health professionals, transport workers and community organisations, among others. The Fairford case illustrates the first stage of this process. Someone noticed something they considered sufficiently unusual and reported it. Police then assessed the information and decided what response was appropriate.

This distinction matters. It is not the public’s responsibility to establish whether something is terrorism. Nor should people be expected to investigate or confront those they find suspicious. Their role is to provide information and let trained professionals assess its significance.

This logic is also central to Prevent, the UK government’s strategy for stopping people from becoming involved in terrorism. Prevent operates partly through safeguarding and early intervention, along with the Channel programme. Channel provides multi-agency support for people considered to be at risk of being drawn into terrorism. The guidance explicitly recognises the role of professionals and others with concerns in making referrals.

In more than a decade of studying Prevent and Channel, my research has explored how counter-terrorism has increasingly become embedded in everyday institutions and practices. It extends the responsibility for identifying potential risks beyond specialist security agencies to members of the public. There is, however, a difficult tension at the heart of this approach.

Encouraging people to report genuine concerns can help identify threats at an early stage. But asking society to become more alert to “suspicious” behaviour also raises the question of what, exactly, is interpreted as suspicious.

This is where the concepts of “securitisation” and “suspect communities” become useful.

Securitisation describes the process through which issues, people or behaviour come to be understood primarily through the lens of security and threat. Over the past two decades, particularly after the July 7 terror attacks in London, scholars have raised concerns about the potentially stigmatising effects of Prevent and its referral processes.

This body of research has examined how Muslims have at times been constructed as a “suspect community”. That is to say, a population subject to heightened scrutiny or suspicion based not on evidence of wrongdoing, but on perceived group membership or identity.

This is not an argument against public vigilance or against Prevent. Rather, it highlights a central challenge: how do we encourage people to report meaningful concerns without encouraging them to profile other people?

That distinction is particularly important when suspicion can attach itself to religion, ethnicity, political views, clothing, language or appearance. Such characteristics do not, by themselves, constitute evidence of terrorist activity.

So what should the public do?

The principle is simple: observe and report, rather than investigate or confront. If something appears genuinely concerning, people should focus on specific behaviour and circumstances – what they have actually seen or heard, where and when it happened, and whether there is an immediate risk.

No one should put themselves in danger to gather more information or attempt to assess someone’s political or ideological beliefs. That assessment is the responsibility of police and counter-terrorism professionals, working where appropriate with established multi-agency panels (Channel, for example).

The events at RAF Fairford raise questions that extend well beyond one airbase. Public reporting can be an important component of counter-terrorism, but effective vigilance requires a careful balance between awareness and suspicion.

The challenge for a democratic society is to make citizens useful sources of information without turning them into amateur intelligence officers. Crucially, it’s about making sure that particular communities do not feel that they are being watched for no real reason.