I knew Joker was a film whose relationship to society today is a rich – and sometimes fraught – one. But until I saw it, I hadn’t realised just how pertinent a film it would be. Set in dystopian Gotham of the 1980s, it’s a world where the vulnerable of society, such as single mothers, the elderly and people with mental health issues are crammed into crumbling housing projects, while super-affluent bankers live it large. The villains in Joker are the filthy rich, such as the bullying, Trump-like Thomas Wayne who blames the poor for their own poverty as he campaigns to become mayor.

This is first-person cinema told from the point of view of someone with mental health issues. The character of Arthur Fleck is an authentic and well-researched depiction of a man with borderline personality disorder. At times, it felt less like watching a superhero movie and more like a social drama depicting a real-life horror story of austerity.

Played with corporeal commitment by Joaquin Phoenix, Arthur has a neurological condition called Pseudobulbar Affect, most straightforwardly explained as spontaneous and uncontrollable laughter at inappropriate moments. The scene where Arthur is confronted by a woman on a bus who becomes irritated by his laughter is a situation that will be all too familiar to anyone who has experienced firsthand the frustration, misunderstanding and sense of helplessness involuntary mental health conditions can cause. It’s not Arthur who has the problem, though – it’s an uncaring and misunderstanding society and that’s what this scene brilliantly conveys. Joker puts us in the shoes of the Other, a disabled man oppressed by the able-bodied.

People with mental health issues are feared in society – derogatory terms such as psycho or nutter are part of everyday conversation. We live in fear of “the insane” and avoid them on the street or move away from them on the train. The truth is that the vast majority of people with mental-health issues are the real victims. Those with non-visible disabilities face everyday hostility, persecution and lack of care. In her recent book Crippled: Austerity and the Demonization of Disabled People, Frances Ryan writes that the new fit for work tests can be linked to 590 extra suicides in England.

But Joker isn’t just the standard disability tragedy narrative that we’ve come to expect. It’s about someone with a disability biting back. Watching the hordes of Joker’s acolytes descend on Gotham in revenge for their degradation at the hands of the wealthy had the audience I watched it with cheering. Joker’s Network-style takedown of a talk show that seeks to ridicule him made me wonder what would have happened if the Block Telethon protest by disabled rights activists who stormed the live ITV Telethon broadcast in 1992 had gone further? At the time there was a sense of anarchy, mayhem and poking fun at the charity culture that oppresses the disabled. The actions of those disability rights activists contributed to the introduction of the disability discrimination act almost 25 years ago.

Joker might just be a classic of disability cinema, a film that takes the experience of the outsider and makes us root for them. I can’t think of a more subversive mainstream film, especially not in the sanitised, spandex-clad, wholesome worlds of the superhero genre. Unlike Heath Ledger’s Joker, Arthur Fleck’s violence isn’t chaotic, it has angry purpose, and he unwittingly creates a vent for the dispossessed. I think the film will divide the disabled community and I am sure some people will take issue with the depiction of mental health. Maybe though, we’ve seen enough of disabled people depicted as pious martyrs, and it’s time the victims fought back. Not by shooting people, but with smart, anarchic direct action.