Backstage, on the second night of the Rolling Stones' Bridges to Babylon tour, most of the world that will cosset and comfort them over the next year is up and running — a world that is serviced by at least six chefs, including a dedicated dessert chef, and that allows two full-time tour employees to have their job listed in the tour program as Backstage Ambience. In the area known as Bar Babylon, I float on the edge of a conversation with some non-performing Rolling Stones insiders. The hot topics of conversation: the best face creams, the rise of Krispy Kreme donuts. Over on the other side of the room, Keith Richards greets the visiting blues wives (Muddy Waters', Willie Dixon's). Keith's father, Bert, wanders by, smoking a pipe, talking about the twenty lengths he swims each day. Ronnie Wood has some glitter on his face, which he excuses as (a) "posh cocaine" and (b) a side product of all the women he has to greet. "Where's wardrobe?" he asks. "And why am I asking now? We've already done one show...."

Keith Richards is scooping ice into a glass with his right hand when we are introduced. My first moment with him. Warm pirate grin; ice-cold handshake.

These shows start with a bendy, overexcited, unanchored "Satisfaction." Each Rolling Stone easily slips back into role. On Mick Jagger's face, there's the determination and the scowling effort and, when it's going well, that swagger.

He shimmies and contorts himself in a flurry of hyperactivity, always as though he is trying to prove something. Charlie Watts has that slightly bemused, patient look, his head turned slightly to one side, half-smiling: It's silly, really, isn't it? Ron Wood assumes his customary jack-the-lad demeanor. Whenever a camera for the overhead screen comes close, he displays his casual repertoire of daftness: the stuck-out tongue, the stupid face. As for Keith Richards... anyone who is cynical about the Rolling Stones' motives in touring the world once more — as plenty, quite reasonably, are — would struggle to explain Richards' exploding grin, at once childlike and old-man wise, stuffed with delight and reverie.

This is the Bridges to Babylon tour. Except... well, I'll let Mick Jagger explain it. "We haven't got a fucking bridge yet," he pouts. It won't arrive until ten days into the tour. "I ordered it," he laughs. He says it's like decorating your flat: Everything's supposed to be ready for a party on Friday, but when Friday comes, there are no curtains.

"And," he repeats, "there's no fucking bridge."

What's the worst part of getting old?

Ronnie Wood: When your ankles start to change color [lifts up an ankle and shows off discolored blotches]. It's not serious. It's probably just broken veins. I still feel like I'm twenty-three. My kids are, like, "You're so old." That's the hardest thing about old, when the kids kind of rub it in.

Mick Jagger: I suppose you do think about the time that's allotted to you more than when you were younger. The mortality thing obviously has a stronger pull for you. It's an imminent truth; it's not necessarily a bad thing. You realize — much earlier than my age now — that you won't be able to play for England's football team, just to take a really crass example. So you can't have that life again. Unless you believe in reincarnation or whatever. Reincarnation? That's a whole other question. I find people who talk about that sort of thing in interviews idiotic. And I don't want to go down with them.

Charlie Watts: It's only if my wife mentions growing old, because I think it affects women a lot more than men, this stuff. It'd be nice to be rich and grow old — I'd hate to be shuffling 'round Brixton Market in a pair of slippers. Then again, I'll probably be shuffling 'round the garden.

Keith Richards: I haven't found it yet. I still zoom around and do what I do. I'd hate to have to go 'round thinking about [derisively] health and shit like that. It's never occurred to me. This is what I am, this is what I've got, and I do what I do. It's such a sturdy frame, this; I even abused it to see how far it could go, but that was a long time ago. Hey, I've got the measure of this thing. [Lights a cigarette] There's only one really fatal disease, I've concluded. It's called hypochondria. And it is deadly.