As well as older sister, Lois [34], you have a 15-year-old sister, Ellie Rae. Did filming give you a glimpse into her life?
Oh, completely. The pressures are immense – way more than I had. It’s really scary. My little sister’s very confident, but you can’t help but worry. There’s constant pressure to be a certain way, to look a certain way. Having an Instagram feed of people knowing who you are – I just find it exhausting. I tend to be that older sister going, “Your phone’s out at the table, put it away.” It’s so important to connect.

Your dad is a renowned actor, and you’re often referred to as “Ray Winstone’s daughter”. Is it frustrating being defined by the man you’re related to?
I find it quite lazy. I’m very proud of where he’s come from and what he’s achieved, but I’ve been on set when people have been talking about him and I have had to say, “Excuse me, I’m at work, this is important to me. You’ve got to hold your chat about how you got off your face with my dad at the pub.” Would they do that to Sir Ian McKellen’s nephew? No.

The divide between London’s rich and poor is really exposed in Ellen. As someone who grew up in London, is that something you’ve seen becoming more and more prevalent?
This film could have been shot in the Nineties – nothing’s changed. The rich are getting richer and the poor are getting poorer and [politicians] just seem to be filling the holes without understanding where the cracks in society are happening. It’s so bullsh*t what you have to do to be in a safe position.

I lived in an amazing house in Notting Hill and opposite was an amazing estate – that’s the beauty of London: no divide. We’ve always had this really strong opinion on unity and society and community and there’s a certain breed of f**king politicians who have got people’s backs up and forced them into corners to vote for certain things. And it’s like, hang on a minute…

I don’t know whether I’m going to put my son in a public or private school – if he goes to a private school, will he get shot down because of his background? I went to a very lovely state school, it was incredible. I feel that’s all getting chipped away and it’s broken society. Certain people are very vulnerable and that’s what politicians are doing, I’m afraid; they’re exposing people’s vulnerable tendencies. It’s gross.

You sound pretty passionate about class and politics – has becoming a mother increased that?
Yeah, all while sitting on a mountain in Sicily… [laughs]

What else will you be doing in Sicily?
I do quite a bit of stargazing. Me, my mum and dad are really into astronomy; at the moment Saturn is above Mars. I’ve been watching The Planets, an amazing old show about the solar system. And my sister has been reading me the Harley Quinn chronicles – my lovely friend Cara [Delevingne] is in Suicide Squad. We’re mixing it up in the Winstone household.

Girl aloud: actress Jaime Winstone chats to Stylist about her latest role, planet watching and politics