Or are they just post-pubescent sharks smelling blood? Can they tell I'm the sort of person who used, a long time ago, to turn sweaty at the sight of them?
They throw themselves on to seats on either side of me, so I'm surrounded. They don't do anything specific. They know they don't have to. And avoiding eye contact is never the answer. I try to stare both as much and as little as I would at anyone onthe Tube.
Their clothes are, naturally, black. Regulation leggings; flashes of PVC or nylon here and there. The pink-violet hue of bad skin shows through foundation several shades too dark and several millimetres too thick. Leather thongs twisted around their
wrists, bitten nails, the obligatory maroon polish chipped down to the centres. All clutch empty polystyrene McDonald's cartons.
One is quite pretty in a scrawny sort of way. Wide-apart oval eyes, cheekbones, ratty hair. Kate Moss on a (very) bad hair day. Another is butch - all scowl and shoulders, short curly hair, trainers, anorak. Sucking at a Coke. It's these last two who do all the talking. The rest look on and giggle, glassy-eyed courtiers.
"What's your fave car then?" asks Anorak.
Kate plays with her polystyrene carton. "Rolls-Royce."
"Mini," - raucous laughter. They look so tough. It's funny that they still play dormitory games.
"Fave place to get married?"
"Toilet." Again, hysterics.
I turn the page of my book. Without reading a word.
"What's your fave type of person?" Anorak's wiggling her thumb through the side of the carton.
"Boyfriend with his pants off."
All eyes slide in my direction. "Worst?"
They're bent double with laughter.
I know there is a funny side to this. But I am unable to find it. I grope around in a darkness made of my past. I'm tense with the memory of a particular kind of tyranny: the malicious, totalitarian, false logic of a gang of girls.
They don't do anything, these girls - nothing that you could explain and get sympathy for, anyway.
When I was seven, there was Veronica, who made me share a loo seat with her. I didn't like it - why didn't I get off? Because she said she wouldn't be my friend if I did.
At nine, I'd managed to find more friends like her: when the bell signalled the end of break, they forcibly hoisted me on to the wire litter bin on the wall. I was small then (frustratingly, I grew late) and was stranded until a teacher found me and
toldme off. More than once. I never told on them - it never occurred to me. Or maybe it did and I knew I needed "friends".
At 13, Joanna Smedley (also huge) practised her judo throws on me and sprained my shoulder. Then she took me down the sewage farm and tried to make me smoke a cigarette and when - priggishly - I wouldn't, she said she'd slit my throat if I ever toldher mum.
"I know someone who's been to a pro," she said. "Bet you don't know what a pro is."
"I do," I replied more in hope than expectation. "A professional."
A look from her was all it needed.
I don't think these girls were bullies. They just took advantage of my desperate longing to be liked (and my inability to choose friends).
I still know Joanna and she's quite nice now. In fact, she goes out of her way to be friendly on the (increasingly rare) occasions we meet. My mum can't understand why I'm not more sociable, why I don't take it further. After all, we're both in London, both have kids. She thinks childhood friends are important. Not when you don't want to be reminded of the child you were, they aren't.
I will never relax in Joanna's presence. I will never trust her. (And she is actually very dull. And shorter than me.)
The happier you seem, the more the Joannas appear on the scene claiming friendship, hoping for a bit of whatever it is they think you've got.
I don't play their games any more. I choose my friends these days. I no longer wait on litter bins till I'm found. I'm a mother of three. I know about "pros" and more. If Joanna leaves a message, I don't always bother to phone her back.
And yet now, on the Northern line, six girls momentarily trigger an alarm system I'd hoped was no longer there.
It's my stop. As I stand, they all stretch out their legs. "Excuse me," I say crisply.
No one moves. Eyes on each other. The train grinds to a halt. I pick my way through 12 legs as quickly as I can. I don't trip, don't falter. As the doors shudder open, I turn back to them and with an impressive, Uma Thurman sort of cool, I say something pithy, stinging and unprintable.
Well no, I don't say it, I think it. I know, I know, it's not enough. It'll have to do. It always has.
I make my way up into the wind tunnel of Clapham Common station, my heart still banging against my ribs.Reuse content