On Saturday immigration enforcement officers went to Peckham to pick up a man suspected of overstaying his visa. When they arrived, a crowd of protesters turned up to stop the ‘immigration raid’, blocking the van from departing. When the police turned up, they also found their way blocked. Eventually, they gave up. The arrested man was released on bail.

The Home Office released a statement which said that ‘preventing immigration enforcement teams from doing their job is unacceptable.’ This was accompanied by the universally understood but officially unstated caveat: not that we’d prevent you from preventing officers doing their job.

British law enforcement is based on the principle of ‘policing by consent’. This has traditionally meant police forces winning the confidence and trust of the general public so they can pursue their roles with minimal resistance. Over the last five years this code has been gradually updated. Policing by consent increasingly means ‘by the consent of the mob’, with the enforcement of the law dependent on the goodwill of any interest group capable of mustering a crowd.

Extinction Rebellion, Insulate Britain, Black Lives Matter and other protest groups have shown that police forces tend to back down when push comes to shove. This in turn has encouraged the adoption of increasingly disruptive tactics. Identical scenes played out last year in Glasgow, when immigration enforcement picked up two men in Pollokshields. A crowd formed, the police backed down, and the SNP had a field day. Nicola Sturgeon slammed the raid ‘on Eid, in the heart of our Muslim community’ – neither man was Muslim – as ‘dangerous and unacceptable’.

This line of reasoning takes as read the principle that the threat of violent disorder is the ultimate determinant of whether or not a law is enforced, abandoning the idea that laws are applied evenly and predictably to all parts of society.

This is not to say these are easy situations for the officers on the ground. If they push through with enforcing the law, they risk events scaling into a riot. But failing to act – while easier in the short term – is precisely what causes these tactics to spread; people learn that they work. The understanding that force will be used if necessary is a critical part of maintaining effective policing; you cannot have effective law enforcement if people are widely aware that a mob can overrule the police.

It’s understandable and indeed admirable that British police officers don’t immediately resort to cracking skulls in the style of the French gendarmes, as tempting as it must occasionally be. But we need to find a middle ground between continental brutality and impotence in the face of light resistance.

The first step is to show that these tactics don’t work. Return as quietly as you like, but once the action has been carried out, make it very publicly known. The second is to punish those involved. Take names, addresses, photographs, whatever you need to identify the most egregious offenders, and haul them in front of a court.

And if this doesn’t work, then it may be worth reconsidering our aversion to the European model of law enforcement. Policing by consent relies on the idea that there is such a thing as general public opinion, which in turn requires a degree of ideological homogeneity. The gendarmerie of the continent arose through the experience of attempting to forge together peoples with divided religious and regional loyalties; if the British public is now too fractured for the traditional model to work, then we could do worse than learning from our neighbours.

We cannot have a situation where groups feel they can obstruct the law with impunity, and we certainly can’t have one where they are largely correct in this belief. The law is the law; it has to be enforced, and be seen to be enforced.