A balaclava on a British street is a small declaration: I do not want you to know who I am. Last weekend, that declaration was made in Dover and Portsmouth, where hundreds of men, many dressed head-to-toe in black, turned out against the arrival of migrants by small boat: road blockades, walkie-talkies, faces covered. It looked less like a demonstration than a uniformed show of force.

Some of Antifa’s fiercest enemies now dress like them

That should worry us. There is no democratic entitlement to intimidate the public, assault police officers or obstruct emergency services. But Westminster should be interested in something beyond the spectacle: why do these men believe they need to hide their faces in the first place?

Start with the costume itself, because the choice is not accidental. The black-bloc aesthetic, black clothing, covered faces and group anonymity, was not invented by Antifa, and Antifa is not a single organisation. But anarchist and antifascist activists helped popularise it on the streets of Europe and America. Political tactics rarely stay the property of one tribe for long; once one side proves them useful, opponents learn from them. The irony is difficult to miss: some of Antifa’s fiercest enemies now dress like them.

There is also a more prosaic explanation, and it matters more than the aesthetics. Britain is becoming a surveillance society, and both sides of this argument now believe the state’s machinery is being turned against them. After the weekend’s disorder, policing minister Sarah Jones told the Commons that police were reviewing CCTV and automatic-number-plate-recognition data to establish where crimes had been committed. Fair enough. But it is not hard to hear how that lands with someone weighing whether to join a politically charged protest: the state can find you afterwards.

Opponents, meanwhile, ask why no arrests were made on the night at all. Add facial recognition, smartphones, online activists identifying protesters by name, and the risk of exposure to an employer, and anonymity stops looking like theatre and starts looking like self-preservation. Parliament has responded by giving police new powers to prohibit face coverings in designated protest areas. The result is a legal and technological arms race with no obvious end.

None of this makes the Dover or Portsmouth protesters correct, and a balaclava is not a symbol of liberty. But dismissing everyone involved as a ‘far-right thug’ is politically convenient. It lets Westminster condemn the symptom without examining the disease.

Small-boat crossings are down sharply this year. Yet the scenes in Dover and Portsmouth suggest the anger has not fallen with them. That gap is the real story: this was never only about the number of boats on a given Saturday. It is about whether voters believe the state is capable of controlling its borders at all. When people stop believing peaceful politics can produce results, politics moves from the ballot box to the street.

The balaclavas are ugly. Banning the masks will not remove what lies beneath them. A healthy democracy needs citizens who still believe the ballot box works. When that belief goes, the street starts to dress accordingly.