I still love Mick

"Well, poor Lizzy," she says conspiratorially. "She had drunk too much champagne at a fashion show. I told her not to, but she said there wasn't any water. I thought there was a big fuss made out of a young girl snogging a cute boy. That was a bit unfair."

In fact, despite labelling herself "quite strict" as a parent, she comes across as laid-back. Even the emotive subject of the prevalence of drugs in modelling, an issue recently highlighted by Kate Moss's career implosion, doesn't worry her unduly.

"My kids are very against drugs, as am I. Well, they did grow up looking at Keith Richards. It sorta puts you off," she says, with a wicked laugh. "But I feel sorry for Kate. I think she's a really good model and I do hope she gets sorted out and comes back working."

Personally, she says, she finds all the fuss hypocritical. "I mean, she's not a minister! It's not like it's brain surgery."

Jerry's relaxed approach even extends itself today to the subject of her errant ex. In the past, she has been fairly caustic about Jagger's behaviour during their 23-year relationship, but today, she restricts herself to gentle rebuke.

"Sure, he wasn't a great husband, and I could gripe and grouse, but I think that's old hat." And, as the hands-down winner of the bitter public relations battle that followed their split in 1999, she can afford to be magnanimous.

Tellingly, she remains the Jagger family matriarch. Mick's father, Joe, comes around for lunch every Sunday; Mick's daughters Karis and Jade drop their children off to stay the weekend with "Grandma Jerry" and Mick's brother Chris is also a regular. "And, at Christmas, I've had Bianca and Marsha," she says, of Jagger's two previous significant others. (Though significantly, L'Wren Scott has only made an invitation to tea.) "I kinda got an open house."

The only member of the family who doesn't seem constantly to be hanging around Jerry's sitting room is Mick himself. But Jerry insists that their relations are "very friendly. We talk on the phone almost every day. I've known him 30 years. He's a great father, and a great friend."

She says this with so much emphasis that you wonder if sometimes she wishes they were still together. "Of course, I often do," she says, surprisingly. "I still love him. But it made me so unhappy. I was unable to do anything because I felt so depressed."

It is not a coincidence, she says, that her acting career only took off once she and Jagger had parted. "If you're in an unhealthy relationship, it's bad for your self-esteem. You have so many ups and downs that you can't be consistent enough to do something as stressful as this."

Since playing Mrs Robinson in The Graduate in the West End, she has been constantly in demand as a performer. "Normally most actresses are stopping at 40 - I was given a really big break," she says exultantly.

Perhaps she's making up for lost time, and all those years she spent running Mick's social life. Right now, her career can only be described as frenetic. On top of the acting, she's designed a range of hosiery for Charnos (including the slightly weird tights she's wearing) and has voiced a nun in the controversial cartoon Popetown, banned from the BBC after complaints from Catholics.

Later this month, she's going to be presenting Fashion Rocks with Jeremy Irons, an evening that requires eight changes of dress and will see her sitting on the Prince of Wales's table. And she is fronting a reality TV show, Kept, on VH1, in which a gaggle of 12 unpolished American hunks compete for her approval.

The winner gets a luxury apartment, an Amex Gold Card and the opportunity to squire Jerry around. Was she tempted by any of the toyboys? "Oh, yeah," she says, unconvincingly. "They were gorgeous guys. So you never know." On the subject of what's really going on in her emotional life, she is more discreet. "I'm dating," she says primly. One special man, or lots? "Just dating."

She won't rule out marrying again. "I'm grown-up. I don't want children, I'm financially independent, I don't need to get married, but part of me believes in true love, marriage and companionship and would like to have someone to spend the rest of my life with, not to be lonely."

The snag seems to be her children, Gabriel, seven, Georgia May, 13, James, 20, who is studying drama in New York, and Lizzy. All of them still live with her in her Richmond mansion (even Lizzy, who has moved out but only as far as a cottage in the garden).

"My home is my children's home and I would never force someone on them. They would have to absolutely adore him," Jerry explains. And this seems a remote contingency; like most offspring of divorcees, they feel no replacement is good enough. "They don't seem to like anybody," she wails. "They say, Mum, why do you need a boyfriend anyway?" And, laughing mischievously, she heads to her dressing room to prepare herself for her public.

High Society opens tonight at the Shaftesbury Theatre (020 7379 5399).