© Provided by The Guardian Photograph: Kevin Frayer/Getty Images

‘We will not at this stage be checking the items in baskets and trolleys to see whether it is a legitimate necessary item,” Nick Adderley, chief constable of Northamptonshire, warned last week, “but if people do not heed the warnings, we will start to do that.”

There was a time (just a month ago, in fact) when “policing your diet” meant little more than government ads about five a day or Jamie Oliver sounding off about “junk food mums”. Now we are threatened with an actual police officer standing at the checkout rummaging through our trolley.

One should be wary about being drawn into a moral panic over a moral panic – that, just as the actions of a few people flouting lockdown regulations are turned into a national crusade against rulebreakers, so the comments of a few over-officious police officers come to be taken as the norm. There is no law, even in these surreal times, which sanctions the police to make moral judgments on your shopping. Adderley’s comments were shot down by the home secretary, Priti Patel, and withdrawn by the force.

The chief constable’s remarks follow, nevertheless, a pattern of police forces beginning to see themselves not merely as guardians of the law, but also as our moral guardians, from using drones to shame walkers in a deserted national park to defining what is an essential journey. And the question this raises is not just about the boundaries of intrusive policing in the midst of a pandemic, but also about how we might expect to be policed in the post-pandemic world.

There is beginning to be talk about what may be the government’s exit strategy from the lockdown – how and when will we return to a normal state of affairs? The answer depends partly on what we mean by “normal”. And when it comes to policing, we may well be faced with a “new normal”.

A year ago, China’s social credit score system and mass surveillance programme were viewed in the west as “Orwellian”. Now they are seen as providing essential tools in the fight against coronavirus.

Mass surveillance has allowed the Chinese authorities to track the movements of suspected coronavirus carriers and to identify with whom they have come into contact. As the lockdown is eased in cities such as Wuhan, phone apps have been introduced that classify everyone with a colour code — red, yellow or green — that indicates contagion risk and determines who can travel or access public space.

Other countries have begun to adopt similar techniques. South Korea has been lauded for its mass testing programme. But that programme rests upon an intrusive tracking system, using a combination of phone location data, CCTV footage and credit card records to trace people’s movements.

The EU has the strictest privacy laws in the world. That hasn’t stopped the European commission from asking telecoms companies to hand over data to allow governments to track population movements. In Britain, the NHS is developing an app that traces close contacts of people carrying the coronavirus and advises them to self-isolate. It may also be used to provide “immunity passports” to those deemed no longer to be at risk. The system will be voluntary, but raises many questions about ethics and personal liberties.

These are not normal times and there is a good case for more intrusive policing and surveillance measures to stem a pandemic. But temporary responses to specific emergencies have a habit of becoming permanent, especially, as historian Yuval Noah Harari observes, “there is always a new emergency lurking on the horizon”. We only have to look at how 9/11 generated a host of surveillance policies that have since become the new normal.

Governments and private companies have long used phone data to track individuals, but the practice has always been contested. The ease with which data sharing has occurred in the pandemic might signal a shift in perceptions. Similarly, the willingness of politicians to make public the private medical details of individuals, from South Korea’s online listing of infected individuals to New York mayor Bill de Blasio’s tweet about an individual who had contracted Covid-19, with sufficient information to allow the press to out him, suggests the crossing of a previous red line.

All this takes place as the relationship between society and the state is being reshaped. From the economic measures announced by the chancellor, Rishi Sunak, to offset the impact of the lockdown to talk of a new “social contract”, there are the beginnings of a debate on the changing role of the state in the post-pandemic world. There is much here to welcome, from the recognition accorded to low-paid workers to the possibility of a more robust welfare state. But with a more expansive state, especially against the background of a weaker labour movement and a more quiescent civil society, is likely also to come increased surveillance and more intrusive policing, for our own good, of course.

© Photograph: Kevin Frayer/Getty Images A Chinese man wears a protective mask as a large screen shows a broadcast of a woman in a protective mask n Beijing, China, on 20 February.

There will be no police officer inspecting your grocery basket, but there will undoubtedly be increased digital snooping. Local authorities and police forces already use data mining techniques to classify individuals and to predict future outcomes on everything from which child might be in danger to where a crime might occur. Such techniques will only become more entrenched in the post-pandemic world.

China has demonstrated how to utilise digital technology to enforce social control. Liberal democracies are adapting those techniques for their own purposes. It may turn a public health emergency into a public order issue, but it won’t stop the next pandemic. A properly thought-out and funded health service and social care system, widespread testing and decent statutory sick pay will do more to mitigate its impact. But it will make liberal democracies less liberal, less democratic, more monitored, more policed.

• Kenan Malik is an Observer columnist