But it’s not just sex. It isn’t. No, no, I’m not being dirty. Not like when mum caught me in the bathroom, caught me with the magazine. And she made me scrub with the pumice stone: made me scrub my hands and . . . no, that’s the past. I don’t want to remember it.

Saturday

No call again. I went out for a walk, up towards the college. I wasn’t sure if Siobhan teaches there at the weekend; thought I might bump into her. I didn’t.

When I got home, I knocked on Simon’s door.

‘Enter at your own risk.’

I went in. The room stank of dope and sex. No sign of Natalie. Simon was on his iMac, looking at porn on the Web. The girl on the screen looked very young; I had to look away.

‘Did anyone call for me?’ I asked.

He reached for his cigarettes and lit up.

'Yeah...actually, some chick did ring.’

‘What? When?’

‘Yesterday afternoon when you were at work.’

‘What did she say?’

He grinned. ‘She asked if I wanted to save money on my gas bill.’

‘You git.’

‘She was nice, actually. Maybe I could have fixed you up on a blind date.’ He laughed and coughed simultaneously.

In my mind, I grabbed hold of his stupid, grinning head and shoved it through the screen of his computer. In reality, I just muttered, ‘Arsehole,’ and left the room.

‘Don’t get eggy, Alex,’ he called after me. ‘It was only a joke.’

I came into my room and slammed the door. Then I turned on my own PC, staring at the flickering screen while it booted up, the hard disk grinding away. I could see my reflection in the monitor screen. My hair was all over the place and my eyes looked puffy. I needed a bath.

But if the phone rang while I was in there . . .

I logged onto Facebook and typed Siobhan's name into the search bar. There were five Siobhan McGowan's in the UK, plus some more in Ireland and a page full in the States. Two of them were listed as living in London on the search results. Of those two, one had a picture of a baby as their profile picture; the other had a picture of a cat.

Siobhan doesn't have a baby - but I remembered her telling us she had a cat when she first introduced herself to the class. I clicked through. Because her privacy settings were preventing me from seeing her full profile, I was only able to see a small amount of information, including the fact that she had 82 friends. Twice as many as me. I scanned the list. None of the others from class were on there.

My mouse cursor hovered over the 'Add as friend' button. Should I do it? Why not. After all, we were friends, weren't we? Certainly better friends than half of the people I have listed as friends, most of whom are colleagues or people I haven't seen or wanted to see since I left school.

I clicked the button then had a tremulous little daydream about how long it would be before I saw the words 'In a relationship with Alex Parkinson' appear on her page.

Then I hovered over the 'Poke' button but thought that was taking things a bit too far.

For the next two hours I refreshed the page repeatedly. I learned that one of my 'friends' was bored, that another had a cold, and that one of them had just finished watching the second series of Prison Break on box set. But Siobhan hadn't yet confirmed me as a friend. I checked Twitter but all I found was an account in the name Siobhan MacGowan with a single tweet that had been made six months ago: 'So this is Twitter, eh? Wonder what all the fuss is about. Am going to tweet every day.' Couldn’t be her, unless she’d accidentally added an extra ‘a’ into her surname - unlikely, I’d say.

Monday

I decided this morning it was time to stop moping around. Stop being pathetic and passive. Do something, Alex. I went into work with a plan, albeit a dangerous one. I was going to commit one of the few sackable offences.

I sat down at my desk and put my headset on. My supervisor, Jackie, looked over at me, making sure I wasn’t wasting time before logging on. As we’re consistently being told, Bookjungle is the biggest online retailer in the world – not that you’d know it from our wages – and we have to keep our customers happy by letting them talk to us like we’re shit and not keeping them waiting when they want to tell us this.

I took a couple of calls from people moaning about delays in receiving their books, then did what I’m not supposed to do.

Checking that nobody was watching, I went into what we call the ‘back office’, the part of the computer system that the public can’t see. It’s the database where we keep all our customers’ details. We need to be able to access it in order to answer their queries: we can see their address and all the books and CDs they’ve ordered. But we’re only allowed to look up the details of customers we speak to, and only if we need the information to deal with their enquiry, to prevent you looking up the details of your friends and enemies. To deter us, the system generates random reports, which mean that you have to be able to show the supervisor that you spoke to the customer you were looking up. These reports only capture one in fifty of the customers we look up, but it’s not usually worth taking that chance.

Today, it was worth that chance.

I was quietly confident that Siobhan would be a customer of ours. After all, we are the biggest of our kind, and anyone who reads a lot, like Siobhan must, was more than likely to have ordered a book from us.

I typed her name.

There were 13 Siobhan McGowans on the database. Most were in Ireland, but three were in London, one more than on Facebook. Two of them had North London postcodes. I wasn’t sure which one it would be so I looked at them both. I felt jumpy and sweaty as I hurried to look up the details. The first Siobhan McGowan had bought a few CDs (Norah Jones, Gareth Gates – Jesus wept) and one Delia Smith cookbook. Surely that wasn’t my Siobhan? I’d be very disappointed if it was. I clicked on the second Siobhan and looked at her list of purchases. It was huge. I quickly scanned the list: Ryan Adams, The Cure, Belle and Sebastian, Sting…well, nobody’s perfect. And among the many books was one about teaching creative writing – and Tara Lies Awake by Siobhan McGowan! In fact, she’d ordered her own book several times. I clicked another icon and there were her personal details. Her home and mobile numbers and email address. I copied them, pasted them into an email, then sent it to myself at home, deleting the message from my sent items folder.

I couldn’t concentrate for the rest of the day.

All I could think was, I know where she lives.

Victoria Gardens was a pleasant little street: nice and quiet, curving off the main road, a small Victorian terrace, aptly enough. Close enough to Camden to be hip, and close enough to Hampstead to be respectable and safe. Siobhan lived at number 54. I walked down the odd-numbered side of the street, trying to act casual, trying not to look like I was reading the numbers on the doors. I was having a job in the dim light anyway, but luckily number 54 had a big brass sign on the front door. Siobhan’s house. Just a few feet away.

Close enough to sense her.

After this initial recce, I came home to check there were no phone messages. There weren’t. Then I went on to Google Maps and found the location of her house. It was only a thirty minute walk from my place, if I took the short cuts I carefully worked out.

I couldn’t phone her because she’d want to know where I’d got her number from. Oh, I was snooping on the computers at work, breaking the Data Protection Act, Siobhan. No. I couldn’t do it. I couldn’t email her either, for the same reason. But I could walk by her house again, and maybe, just maybe, I’d get lucky. She’d come outside and look surprised and I’d say, ‘How strange, I’ve got a friend who lives down here. I’ve just been to see him. Yes, I’d love a cup of coffee. You lost the card with my number in? No, don’t worry, I knew it would be something like that. And I do have a mobile, by the way, it’s just been nicked. Ha ha.’