Joanna Briscoe: At the Sharp End

You're either one or the other: tea-drinking older sibling or vodka-swilling kid sister

The world is essentially divided into spods and rebels, into responsible older siblings and naughty little sisters. Such status is often defined simply by birth order: as a neo-grandma I number a groaning preponderance of eldest children among my friends, all earnestly striving, counting up their vegetable portions and attending to their ageing parents, a chippy admixture of guilt and industry.

It's also an attitude of mind. You're one or the other: you're either sitting at home reading about Pete Doherty, or you're out there off your face being Pete Doherty. That's why it's skin-itchily embarrassing when Emma Thompson bungs on her new vamp act though she's an Oxbridge and Oxfam girl to the core, or when someone like Courtney Love affects spod spectacles when she should be throwing up through a fresh trout pout. One must stick to one's fate.

Different worlds often delightfully collide. As the Booker shortlist was announced, Kate Moss was busy hoovering up cocaine, to the entertainment and even edification of a nation of older sisters. Now, thanks to her, I know exactly how many grammes can be divided into how many lines, their precise street value, and how to smash up a 1964 Fender. I was contemplating Banville's Nabokovian prose style while reading about Moss's highly stimulatingly lifestyle, my Daily Mirror tussling with my thesaurus and my nose pressed to the tabloid as I positively snorted up the details.

The ungovernable ones - those providing the cocaine epidemic that's placing a burden on NHS resources; the bare-legged dipsos who'll soon be barfing merrily for newspaper lenses when 24-hour pub opening is legalised next month; Charlotte Church and her cohorts - they are all are doing the rest of us a service. As a keen follower of their exploits I feel like I'm living a rip-roaring life on the edge, yet I don't have to set a foot out of the house. It's like watching someone else fannying around on reality TV so you don't have to.

As an author, I knew it would look better on my biog if I could have overcome a smack habit, run guns, worked in a mortuary or followed a Bedouin tribe, but the truth is that any of that stuff would have had me in tears, racing back to mummy and my keyboard. I did seduce my mother's female friend, follow her to Australia, and forge several other unwise liaisons in my twenties. Will that do? Even then, however, I was drinking tea and hooked on early nights. Take a square out of its environment and it squeals.

Mind-expanding

I attended my first music festival this summer. "Yeah, sis, yeah honestly sis, I know you'd think Glastonbury's shit, but you'd really like this one, honestly," my younger sister, who went to school with Domino Harvey and probably views me as a piece of taxidermy, claimed.

I hate it , I texted her within an hour of arrival. "If you could just open up your north London barrack of a mind," the snarling answer came pinging back.

But it seems that to prise open one's barrack of a mind at such events one must simply consume addictive narcotics, and since I have more of a tannin habit, I don't get it. I can't really see the appeal of an expensive excuse to take drugs and get drunk with a pack of pissed people from Islington while some idiot waylays you by ululating about their 40-quid-a-rub reiki tent, all masseurs fully untrained.

And the head-nodding worship of "star" DJs just gives me the giggles. DJ-ing is a skill ; it is not an art. My teenage neighbour, too, can make compilation tapes. I mean, I mean, download-sample-thingy compilation digital sequences.

Surrounded for two days by overpriced noodles, juggling paraphernalia, smoothies, and 50-quid hammocks and stalls dedicated to laughing at Hindu imagery, I was relieved when a bluestocking soulmate summed it up: "Really, all I wanted was a library tent."

The Max factor

What is it about that Joanne Lees, the neatly dressed Hove travel agent with the murdered boyfriend in the Ozzie outback? I slightly mix her up in my head with Lindy "dingo baby" Chamberlain, but that must be the outback part confusing me.

Lees is the victim and not the villain, so why is it we view her with a reflexive soupçon of suspicion? Is it because she's young and quite pretty, with alarmingly blue laser eyes? Is it because she looks like a secret vamp from a Fifties typing pool who dared to have a shag on the side?

"As soon as I saw her face I thought she looked very sinister and a bit devious," announced a friend in doom-filled tones.

It's the Maxine factor. Myra's dead, Maxine's in disguise, so here's an innocent replacement female to gawp at. From Salem to Greenham and back again, it's always nice to know that misogyny is flourishing.

'Sleep With Me', a novel by Joanna Briscoe, is published by Bloomsbury

Deborah Ross is away