Sometimes, Carrie thinks of each of her three best friends as a sort of fairground mirror of herself - reflecting what she might have been if her life had been just a little different. Sharp-angled with independence; softly rippled with idealism; stretched tall with self-belief.

Sometimes she wishes she could swap places with one of them.

The concept is appallingly arrogant, she knows. They are themselves: Miranda, Charlotte, Samantha. Not cynical!carrie, romantic!carrie, sexy!carrie. Maybe that could be a topic for her column some time: "When we look at our friends, how often do we see beyond our own reflections?"

It's odd to think of her friends doing the same to her: imagining what they would be like if they had some of her characteristics. But she supposes that Samantha must have been doing something like that, when she announces that she's thinking of having breast enlargement surgery; and that she wants breasts like Carrie's (although she admits that Charlotte's are rather nice too).

Carrie is surprised how much of an effect this unusual compliment has on her. Over the next few days the thought keeps popping into her head: Samantha likes my breasts! And each time she thinks it, she finds herself walking a little taller; moving with an extra spring in her step; smiling a secret smile that reaches right into the corners of her eyes. She catches herself glancing at the reflection of her breasts in shop windows; admiring them in the bathroom mirror as she undresses - the gentle, full curve of their profile, the perfect rose flush of her nipples.

She'd always known her breasts weren't bad, but now she's gained a new appreciation of them; as if she's looking at them through Samantha's eyes. She feels protective - almost maternal - towards them. She chooses her outfits to show them off to best advantage; finds herself noticing those of other women a little more, glancing at theirs and then down at her own as if to say 'yes, they're not bad, but you are fabulous'.

She buys a new bra the day before Miranda's wedding. It's aquamarine; made of a translucent chiffon, through which her nipples are visible. She twists around in the changing room, mirrors showing her from every angle. It boosts her curves in just the right way, making her breasts look like they did when she was eighteen, before age and gravity began to pull them down. God, they were gorgeous then.

She thinks then of her breasts as they were when she was even younger: posing in her bedroom, wearing her first bra, even though she had had hardly anything to fill it. She'd been a bit of a late developer, and remembered the excitement when the small points of flesh had started to rise from her chest: delicate yet determined. They had been so tender and so beautiful; the promise of things which she could not articulate, still not quite in reach, but suddenly so much closer. She remembers lying in bed and slipping her hand up to her chest, feeling the wonder of this new shape her body was assuming.

She describes the bra to Samantha that night on the phone. Samantha seems a little distracted: Carrie supposes it's because she's thinking about what she'll wear, once her breasts have been enlarged.

The next day, of course, Samantha drops the bombshell. Breast cancer. Carrie desperately wants to reach out and hug Samantha; hold her tight and never let her go; but it's obvious that's not what Samantha wants. Not today. So she forces herself to stay calm, matter of fact, tries not to betray the trust Samantha has given her by telling her this.

Carrie listens, as Samantha outlines what she's found out in the last few days. She imagines the cancer as a weed with tangled roots, reaching its way deep into the flesh, gripping and pulling and twisting and refusing to let go. She winces as she imagines a surgeon's knife cutting into that delicate tissue. And at the back of her mind, a terrified voice keeps repeating cancer, cancer, cancer; and she tries to think of her life without Samantha in it, and it feels like the light's been switched off.

They watch Miranda and Steve exchanging vows. The garden is beautiful; the light is amazing. It would be a perfect day if not for this weight, this shadow, that seems to have come out of nowhere. She longs to tell Samantha how wonderful she is, how much she loves her, but she has no words. She reaches out and grasps Samantha's hand, and tries, with every cell in her body, to send Samantha those feelings through the touch. She hopes, desperately, that some of it's got through.

Sometimes, Carrie thinks of each of her three best friends as a sort of fairground mirror of herself - reflecting what she might have been if her life had been just a little different.

Sometimes she wishes she could swap places with one of them.