How do people react when you tell them you’re a politician?

“It’s often me knocking on their doors, introducing myself as their new MP candidate. But if I get talking to people when I’m doing my food shop or running errands, I will usually tell them quite reluctantly that I’m a politician. It tends to be a mostly positive response and they usually pitch their ideas to me or tell me about an issue that’s bothering them. People are really keen to have their say, and that’s how it should be.”

Do you have a constituent in mind when you’re standing up representing them in parliament?

“Always. It’s one of our principles. In the London Assembly, I work with Caroline Russell and Zack Polanski and we have this written down as one of our working principles – ensuring our ideas are coming from the people of London. It’s our job to bring their voices into City Hall. Almost every single time I’m speaking about an issue or policy, I’m doing it on behalf of someone who brought this to me as a problem, idea or campaign.”

What piece of criticism as a politician has stuck in your mind?

“I particularly dislike it when people make criticisms about my appearance. I feel as though it’s something women have to tolerate in politics, but it really sticks with you. I remember I met a famous columnist many years ago at an event he was covering for his newspaper, and in his piece, he mentioned me and wrote that it looked like I’d put on make-up in the dark because my eyeliner had smudged. That’s all he had to say about me or my work. I was absolutely gutted. This journalist had decided that the most interesting thing about me was not the work I was representing at the event, but my smudged eyeliner.”

What was the last lie you told?

“So, my mum’s coming to visit me later today and she’s staying with me for a week. I’ve definitely lied about how tidy and organised my flat is and what it’s usually like.”

How do you keep your brain sharp?

“I do a lot of Rubik’s Cubes. I learned how to do a basic one a few years ago and I’ve moved on to some of the more complicated ones. I’ve got a mirror cube, which I highly recommend. It’s much harder to solve but it’s so satisfying. I’ve become known for them among my friends and family, and I tend to be gifted quite a few of them now.”

Why should a voter trust you?

“Because we reject vested interests. We just don’t have any. We take our principles very seriously and are transparent. I think far too many politicians have a vested interest. They take money from people who then want to influence their policies, and some of them do it incredibly explicitly. I try to promote openness and transparency in everything we do. As a party, we have strict rules on who we take money from and, more importantly, that it doesn’t mean they’ll be receiving something in return.

“Recently, I’ve started to publish the meetings I have with campaigners and lobbyists, and I’m trying to persuade my colleagues and other parties to do similar. It holds you accountable, and it’s just good practice.”

What would make you walk away from politics?

“I don’t think I would walk away; I feel like I had an awake moment. One of my first jobs was as a medical writer, writing to doctors about how different cold medicines work. I realised I was working for a big pharmaceutical company, and some of what I was doing was trying to market drugs for things that shouldn’t necessarily be medicalised. For me, it was eye-opening. Ever since, especially now that we know what we do about climate change, I couldn’t walk away from what I do. I’d go further and say being awake to things is a good state and we should almost try to reclaim ‘woke’. What’s bad about being alert, awake and seeing what’s really going on? So, now that I know what needs to be done, no, I’m not going anywhere.

“But I do think I was a successful campaigner, on getting 4x4s off inner city streets, securing funding for young people and, of course, on climate change, and if I spent the rest of my life as a campaigner, I think it would be time well spent.”

What keeps you awake at night?

“I work hard so I’m usually very tired by the end of the day, and I tend to fall asleep quite quickly. But if I have to get up for an early morning interview or event, I struggle to sleep. My brain is wide awake because I’m going over things in my mind and I know I have to wake up early.”

Answer The Question is Stylist’s home for all things voting and elections. In the series, we sit down with MPs from across the political spectrum to get to the heart of who they are and, more importantly, why we should trust them with our vote.

“I couldn’t walk away from what I do”: Sian Berry on the climate crisis and the Green New Deal