“The full force of the law must be brought against violent protesters,” David Cameron repeats his mantra, once again, on the evening of 9 December, following the fourth instance of targeted property damage and clashes with the police coming from within the groundswell of student protests against education cuts. The mantra’s combination of “force” and “law” is not intended solely as a call for retrospective legal proceedings, but also summons law-preserving violence in the immediate future. In other words, each repetition of the mantra in the past month has served as foundation and legitimisation for increased militarisation of policing at each successive student demonstration. It has, of course, also served as a clear threat to those who will continue protesting, even if with non-violent methods.

We first heard it from Cameron in the wake of the occupation of Tory headquarters on 10 November, during the 52-thousand-strong, first student march on Parliament. Police presence was minimal that day, complemented by a civility on the part of protesters that only a generally shared belief in liberal democratic principles could produce: fellow protesters in stewards’ vests policing arbitrary railings in the middle of Whitehall; thousands marching past government buildings whose doors were barely secured, even left ajar as their staff walked in and out. Later in the day, the occupation and trashing of the headquarters of the Conservative Party channelled some of the more uncontainable registers of outrage within the march.

It is not clear whether the occupation and property damage was somewhat planned à la black bloc or entirely spontaneous. As one first-person account reasons, given the number of occupiers without masks and the diversity of placards they were carrying, it could be assumed that there was a significant amount of spontaneous participation. Nevertheless, there seems to have been a collective intelligence at work for most of it, a method to the madness, as it were: after all, the target was quite appropriate and the damage accurate. The key rationale of direct action is to put a wrench in the works: if you can’t stop them, make sure to cost them. It was not any old government building that was occupied, but the very headquarters of the political party who are hell-bent on legislating immeasurable structural violence and systemic destruction. It is fortunate that the more mindless moments, such as the fire-extinguisher stunt, did not prove fatal (though, of course, this did not deter authorities from spinning epic lament for the could-have-been martyr).

And so the whole shebang was cast as a scandal for the London Metropolitan Police, with Cameron effectively scolding the police publicly, and the latter expressing “embarrassment” – apparently they had no clue how massive the turnout would be. As goofy as they may like to come across sometimes, the police obviously had their own calculations, presumably attempting to hijack the demonstration to make a point to the government about cuts to their own budget: “It is a reminder that the Government must maintain the number of fully warranted police officers to ensure that policing these spontaneous incidents, along with their everyday duties, can be sustained in the capital,” Peter Smyth, chairman of the Metropolitan Police Federation, concluded. Their ostensible incompetence has also served as a manoeuvre to regain some of the ground they lost following the G20 demonstrations of April 2009, where one man’s death had unleashed widespread public scrutiny of police brutality, including an official review of their methods. Indeed, only days after Cameron’s first call on the force of law, an unnamed senior police officer told the Guardian that the students’ direct action had helped police: “To be frank, this will have done the commissioner a favour. In the past we’ve been criticised for being too provocative. During the next demo no one can say a word.”

Cameron summoned, the force of law delivered: during the second mass demonstration on 24 November, 5000 protesters, mostly schoolchildren, were kettled for seven hours in Whitehall in subzero temperatures, with mounted police charging into the trapped crowd at one point. Then during the third demonstrationon 30 November, by about 6pm, Trafalgar Square was rendered a zone of emergency with three helicopters hovering over what resembled a mass demonstration staged by the police: seemingly twice their size and certainly thrice their number, the officers had formed a double-wall with their armoured bodies to trap a small group of scantily clad kids who had walked out of their schools earlier in the day. Outside this kettle, a wall of mounted police looked on as other troops in riot gear marched in military formation from one point to another for no apparent reason, bellowing “Forward!”. What was clearly aimed to provoke and escalate tension was countered by only a few scuffles, some Christmas carols, and a queue formed by those who wanted to get out.

This Thursday’s clashes with the police, the attack on the Royal Rolls Royce, and property damage in Westminster and on Oxford Street has shown us that there is a determined constituency within this new youth movement who do not rule out the use of physical force in protest. The damage they incur is far from random vandalism. The courage they display in refusing to be intimidated by the increasingly brutal tactics of the police has garnered some recognition from those who’ve found themselves helplessly detained in a kettle for attempting to exercise their democratic right to protest. And yet, the issue remains controversial and potentially divisive.

NUS President Aaron Porter has recently declared that “violent” protesters need to be excluded from future demonstrations. Porter had previously condemned the Tory HQ occupation as “despicable”, announcing that “a minority have undermined us” – the supposed student leader apparently unaware of the performative power of his utterances, thus threatening to undermine all 52 thousand of “us” by his very statement. Though Porter has lost credibility for many in the movement, he is not alone in his position on what he insists on calling, in chorus with the establishment, “violence”. Some share the belief that a relative minority’s use of physical force undermines the clear united message of legitimate concerns. Then there’s the argument that such tactics are used as an excuse by the police for increased repression. There is some truth in both of these positions. But also some bad faith: Several winters ago, those many millions of us who were peacefully exercising our rights to protest against the invasion and occupation of Iraq were left high and dry on the promises of liberal representative democracy, which then went on to murder and maim in our name. And those of us who have been on a demonstration or two know that no police force needs an excuse to escalate repression.

The current student movement is led by a generation that was prematurely labelled “apathetic” by the various forces of hegemony, the only possibility for their political involvement engineered by the same forces as either a career opportunity (be it nongovernmental, governmental or transnational), or sentenced to inconsequentiality by cynical calls from the powers that be for the “right” to “peaceful” protests. Even if we may personally choose to remain committed to non-violent principles, it is imperative that we recognize the crux of the intervention of those who do not rule out the use of physical force in this wave of protests: it is a challenge to the apparently seamless liberal consensus that continues to beget untold injustice and structural violence on a global scale.

Basak Ertur is a lecturer in law at Birkbeck Law School.