Political protest is at the heart of the actor’s latest film, and has always been important to her. She explains why she feels so inspired

On the morning of 16 August 1819, an estimated 60,000 men, women and children gathered at St Peter’s Fields in Manchester to call for parliamentary reform and suffrage for workers. The army tried violently to disperse the crowd, killing 18 people and wounding more than 650. It remains the bloodiest political clash in British history. John Edward Taylor’s fearless reporting of the violence brought it to national attention and later led him to create the Guardian.

When I heard Mike Leigh was making a film about Peterloo, I decided to drop him a line. I sent him a postcard saying something along the lines of: “Dear Mike, I believe you’re doing a film on Peterloo. I would love to be part of it, but if not, it’s wonderful news that you’re bringing the story to a wider audience.”

That was about a year before the film started shooting. He wrote back and said: “Of course you can be in it, I don’t quite know what I’m doing yet. I’ll call you when I do.”

Mike has always been an actors’ director, known for responding to correspondence from actors. I first met him when I left drama school. I did my final-year showcase at Rada, where you get to perform two pieces of your choosing in front of various agents and casting directors. One was a duologue from April De Angelis’s Playhouse Creatures with the glorious Sally Hawkins. We wrote to the casting director Nina Gold – one of the best in the business, who casts Mike’s films – and as a result we were invited to meet him. Sally, of course, went off to work with him immediately and they have collaborated many times over the years; now she is a multiple Oscar-nominated star. I had bits and pieces, such as a day’s work on All Or Nothing, but he is very loyal to his actors. Even if you just worked for him a little, he won’t forget you.

There are no leads in Peterloo – it is truly an ensemble piece, with more than 100 actors. My character, Nellie, appears sporadically, but is very much part of a family unit. I was very fortunate to work with a group of fabulous actors. Between us we not only created a backstory for our own characters, but also for the whole family and the whole street they lived on.

Facebook Twitter Pinterest ‘She may not be an active part of the movement, but she is very clued up on the workings of the world’ ... Maxine Peake as Nellie in Peterloo. Photograph: Simon Mein

Nellie is the matriarch of a poor, hard-working family from Manchester (Angel Meadow, to be precise) and a mother of five. People who have seen the film have been surprised, as they regarded her as not political. I beg to differ. Nellie may not be a reformer or an active part of the movement, but she is very clued up on the workings of the world. She cares passionately about the future, not just for her children and her children’s children, but also for society as a whole. Nellie fears the struggle has been hijacked by a lot of men spouting a lot of hot air. She is a doer – actions not words – but there is the rub ... partaking in direct action at this time could get you the death penalty.

Five years ago, I did a performance of The Masque of Anarchy, Percy Bysshe Shelley’s poem written in response to the Peterloo massacre for the Manchester international festival. Alex Poots, who ran the festival at the time, asked if I would be interested in reading it to an audience, as an introduction to a debate on how our political climate mirrored that of Manchester’s past. Sarah Frankcom was directing it and said: “Let’s do it as a proper performance. Lights, sound systems and you’ll have to learn it ...” It’s 93 stanzas and I was filming [the BBC legal drama] Silk in London during the week. I did wonder: “Is there going to be an audience for this?” It sold out immediately. Two thousand people crammed into the Albert Hall in Manchester for each performance. Why? People felt its power, not only as a reaction to a vital piece of Mancunian and national history, but also in how relevant it is to the political situation today.

A lot of the audience were people who knew very little about Peterloo or the poem. They wanted to talk, to debate. It felt like a really important time for me. I had begun to feel disillusioned with politics and I was trying desperately to keep my faith that another way could be possible. At the same time, it felt as if hope had started to grow again. It felt as if there was a door opening for people who wanted a better, fairer way.

There is still power in mass demonstrations; we must never forget that

The Labour party’s “for the many, not the few” goes back to the last line of The Masque of Anarchy: “Ye are many – they are few.” I joined Labour so I could vote for Jeremy Corbyn. I had always voted Labour, but I never had any intention of joining the party until it became viable that Corbyn might become the leader. We have just had the party conference and, all right, I am biased, but as far as I am concerned, this year has been extremely encouraging and positive. It felt like a proper party conference. Socialism is on the cards again – it is no longer ridiculed as something archaic and naive.

The Peterloo massacre was not something I was taught in school. I had a typical comprehensive history education: kings and queens, nothing about my people, nothing about working-class history. It was only through my grandfather that I gained any knowledge of Peterloo. He gave me a potted history when I was about 12 or 13.

My grandfather had a life-changing influence on me. He never had any ambitions to be a politician – he worked on the assembly line at Leyland Motors – but his life was politics. He was a self-educated man and he had a thirst for knowledge. He was a member of the Communist party. I joined when I was 18. My grandad wanted me to wait until I was old enough to make my own decisions. He warned me: “Getting involved in politics is not a hobby, Maxine. It has to be your whole life; if you commit now, it will take over.” He was right.

Facebook Twitter Pinterest ‘The costumes may be different, but it is the same old battle against authority’ ... Simona Bitmate (right) as Esther in Peterloo. Photograph: Simon Mein

I am not intellectual by any stretch of the imagination. For me, getting involved was about fairness. I wanted an equal world. I wanted peace, jobs for all, nuclear disarmament. I wanted feminism, I wanted to abolish racism. I wanted healthy, fair, progressive politics. I might have been naive at 18, but if so I am still naive now. My goals have not changed – I still want that now.

I left the Communist party at 21, when I went to London to drama school, for no other reason than that I could not fulfil my commitments to it. But I am still a socialist. I decided that if I was going to be political, it would be through my work. I was always sceptical about the effect that television, theatre and cinema can have, but sometimes you see the impact. Take Three Girls – the BBC miniseries about the Rochdale child sexual abuse ring. People stopped me in the street wanting to talk about it, wanting to ask me questions, not about my character, but about the whole piece, about the grooming scandal, how they felt about it, how the series had changed their attitude.

I don’t feel a responsibility as an actor to get people involved in politics – I think that is slightly patronising. My responsibility as an actor is to tell a good story and to play a good part. It depends on the stories you choose to tell. Of course, I am asked about my politics and therefore I am honest about my politics, but I completely understand why other actors do not want to be vocal about these things. That was never in the job description, but it is too much of who I am. I do not go around telling other people how they should feel or think. I am not a Henry Hunt – one of the main characters in Peterloo (played by Rory Kinnear). He was one of the leading orators of the time, who went around the country standing on a box making speeches, wearing his trademark white hat. There was a vanity to him, I suppose, as there is with many politicians, left and right. My grandad used to say: “Politicians, Maxine: frustrated actors.” I will admit it works the other way around sometimes, too.

Watching Peterloo, you understand how impossible it was made for working people to get educated – but people did

Watching the finished film of Peterloo, you really get an understanding of how impossible it was made for working people to get educated, but people did. They fought tooth and nail for it. They went to seek it out wherever they could, hoovering up knowledge and knowing it is power.

To hear the beautiful speeches, political speeches, that the reformers make, at a time when most people were uneducated, is wonderful. Being able to speak that eloquently for that long, with so much knowledge and passion, is something I fear we are losing: that drive, that passion to self-educate. We have had that drummed out of us. Where we are now, it is not possible for hordes of people to go into further education, because of financial restrictions. People do not feel they have any power any more. We have become anaesthetised with debt and fear. We are being constantly bullied into submission.

For me, this is about remembering the struggle, the heartache and the sacrifice people made in the past, but it is also about holding up a mirror to where we are now. Peterloo tells you the history of that time, but it also shows you: this could happen again. The costumes may be different, but it is the same old battle against authority, it is the constant disregard of working people, the lack of respect, the systematic bullying. I know people think I am some sort of extremist, but to me we live in a police state and it is getting progressively worse. You only have to look at the many anti-fracking demonstrations in the north where the police used extreme violence against the protesters to see that.

I think the film will open people’s eyes. Next year is the 200th anniversary of Peterloo, but the timing of it – it feels as if the planets have aligned. People want change now, like they did then. I still believe that unity is strength. There is still power in mass demonstrations; we must never forget that. People say they do not achieve results, but for me it is not always about being successful. It is about stemming the flow. It is about getting under the skin. It is about saying: “We’re here and we don’t agree.” If we stop standing up and shouting, we will be in a very sorry situation.

As told to Steve Rose. Peterloo is released in the UK on 2 November and in the US on 5 April