London

People became outraged by that; it was banned by radio stations in Spain, Sweden, Italy and the UK, and the Vatican condemned its immoral nature. But you know how it works – you get massive publicity. Actually, I don’t believe that was deliberate; I think they were much more naive than that and it wasn’t calculated in any way. I think they were doing what they believed in. They became known as this scandalous couple, but they were just passionate and in love. I believe in that; that’s how I run my own life.

There are loads of archive pictures of the two of them out in Paris and London, just having a good time and looking incredible. They’re captured in this ‘moment’, epitomising that carefree, ’60s attitude, yet they were still really chic, effortlessly stylish.Then there’s the handbag named after her. Unfortunately I don’t have one, but that’s not to say I wouldn’t like one. Apparently she got on a plane, way back when, and dropped the contents of this basket she always carried. She dropped it on this man who happened to be the head designer of Hermès at the time, which was pretty cool. So then he made the Birkin bag for her – this special design where nothing would fall out of the sides. And all because she had so much crap in her bag! Feature continues

In 1971 she and Serge had a daughter, Charlotte Gainsbourg, who is now an actress too. They were together until 1980 when she moved out. He was drinking and went into this horrible depression. I read somewhere that she’d said this was his way of saying goodbye. It’s a sad ending – he must have been the love of her life.

Soon after that, in 1982, Jane had a third daughter, Lou, with actor Jacques Doillon. I’ve met Lou, actually, at an Alexander McQueen show in Paris. She’s an actress and model. She has that same teenage woman quality her mum had.

Jane still has this incredible warmth to her. I saw her in concert a few years ago at the Barbican. It was really nice because she talks to her audience as well as singing, and you feel like it’s just you and her in the room; like you’re sitting down to a cup of tea with her. She’s one of those women who has that rare quality. Marilyn Monroe, Brigitte Bardot, Kate Moss, Jane: they’ve all got that. You don’t find it very often, you really don’t. But Jane Birkin has it and you can feel it.

The new Agent Provocateur fragrance, Agent Provocateur Maitresse, is out on August 31. Available from Agent Provocateur stores and Selfridges (020 7620 2333) from £44 for 50ml.

johnoconnell@timeout.com