When I interviewed McCartney five years ago she was vociferous in her frustration at how few other fashion companies had followed her ethical lead; now, she seems resigned. “This industry is supposed to be about change, but it’s not changing much.” Fast-fashion companies such as H&M, Levi’s and Adidas are more engaged with the ethical debate, “because those bigger companies have more people to answer to. The luxury industry has no one to answer to and they literally get away with murder. But it’s complicated, because there’s an argument that better-made, better-quality clothing is itself more sustainable. Buying a dress for a fiver and throwing it away after a couple of weeks is not environmentally friendly, whatever the fabric.”

McCartney inherited her uncompromising spirit from her mum, Linda, who died in 1998, when Stella was 26. “My mum had a massive influence on me, not just in what she wore and how she looked, but in her spirit. She was married to one of the most famous men in the world and she didn’t wear any makeup, ever. I mean, have you ever seen the wife of a man like that rock up with no makeup on? Because I haven’t, since. That courage, that inner confidence, is something I’ve never experienced in anyone else. I certainly haven’t got the balls to do it. I find everything about her pioneering, and amazing. She had a beautiful ease with herself.” That, she says, is her ideal. “That ease, that freedom and confidence. That’s what I want to help the Stella woman to find.”