‘Honestly, it was just a small scratch. He hardly even cried. There’s a tiny pink mark on his ear, but you probably wouldn’t even notice it.’

Wearily, I thank her, end the call and ring Pam Senior. She’s not in, so I leave a message-a grovelling apology. I ask her to ring me back, hoping that as soon as I hear her voice I will know instantly that she didn’t try to kill me yesterday. Muttering, ‘She ought to be the one apologising to me,’ under my breath, I ring Monk Barn Primary. The secretary wants to know why I haven’t filled in a new pupil registration form and an emergency contact form for Zoe. I tell her I haven’t received any forms.

‘I gave them to your husband,’ she says. ‘When he brought Zoe in for the open evening.’

In June. Two months ago. I tell her to put new ones in the post and make sure the envelope is addressed to me. ‘I’ll get them back to you by the end of the week.’

Spend the week with me. That’s what he said, Mark Bretherick or whoever he was, after I told him how long I was staying, that first night in the bar. He was also staying for a week. This time it’s a week, he said. Business. But I didn’t hear him cancelling any meetings, and he certainly didn’t go to any. I assumed he’d decided to abandon work in favour of me, but surely there would have been the odd phone call… I saw his mobile phone in his room, but I didn’t see him use it, not once.

Oh, my God. I grip the edge of my desk with both hands. He changed rooms. From eleven to fifteen. He told me there was no hot water in his bathroom, but how likely is that in a three-hundred-pound-a-night hotel? I didn’t hear him talking to any of the hotel staff about it. One morning he just told me he’d changed. Upgraded. ‘I was in a “Classic” suite before,’ he said. ‘Now I’m in a “Romantic” one.’

What if he had only ended up at Seddon Hall because he’d followed me? Because I looked so much like Geraldine. And then, because it was short notice, he couldn’t get the same room for a whole week…

I can’t stand this any longer: not knowing anything, not doing anything. I turn off my computer, grab my bag and run out of the office.

As soon as I’m in my car with the doors locked, I ring Esther. ‘About time,’ she says. ‘I was just deciding not to be your friend any more. The only thing that might change my mind is if you tell me what’s going on. You know how nosey I am-’

‘Esther, shut up.’

‘What?’

‘Listen, this is important, okay? I will tell you, but not now. I’m about to go to a place called Corn Mill House, to speak to somebody called Mark Bretherick.’

‘The one on the news, whose wife and daughter died?’

‘Yes. I’m sure I’ll be fine, but if by any chance I don’t phone you within two hours to say I’m out of there and safe, phone the police, okay?’

‘Not okay. Sal, what the fucking hell is going on? If you think you can fob me off with-’

‘I promise I’ll explain everything later. Just, please, please, do this one thing for me.’

‘Has this got anything to do with Pam Senior?’

‘No. Maybe. I don’t know.’

‘You don’t know?’

‘Esther, you mustn’t say anything about this to Nick. Swear you won’t.’

‘Ring me in two hours or I’m calling the police,’ she says as if it was her idea. ‘And if you can’t explain or go into detail then, I’ll push you under a bus. All right?’

‘You’re a star.’

I drop my phone on the passenger seat and head for Corn Mill House.

Police Exhibit Ref: VN8723

Case Ref: VN87

OIC: Sergeant Samuel Kombothekra

GERALDINE BRETHERICK’S DIARY, EXTRACT 2 OF 9 (taken from hard disk of Toshiba laptop computer at Corn Mill House, Castle Park, Spilling, RY29 0LE)

20 April 2006, 10 p.m.

I don’t think I’m going to be able to be friends with Cordy for much longer. Which is a shame, as she is one of the few people I like. She phoned me a couple of hours ago and told me she’s fallen in love with another man, someone with whom she has spent a total of two weekends. She says she knows it’s crazy but she’s only got one life and she wants to be with him. Dermot knows about it, apparently, and is devastated. I don’t blame him, I told her. Last year she insisted he have a vasectomy. He wasn’t keen but he did it for Cordy’s sake, so that she wouldn’t have to keep taking the pill.

She said she couldn’t stay with Dermot just because he’d had ‘the snip’. ‘I’m not that self-sacrificing,’ she said. ‘Would you be?’

I didn’t know what to say. I was thinking, Yes, I must be. For the past five years I have felt as if I’m trapped in a small chamber inside a submarine that’s lost its oxygen supply, and I’ve done nothing about it. I continue to do nothing about it. This evening I was in the kitchen chopping chorizo for supper, and Lucy came up behind me, wrapped her arms round my legs and started to sing a song she’d learned at school. Loudly. I felt that fluttery panic in my chest again, as if I’m a butterfly struggling to escape from a thick, closed fist. That’s how I always feel when Lucy throws her arms round me unexpectedly. I said, ‘Hello, darling, that’s a nice cuddle,’ as the old familiar scream started up in my head: no space, no calm, no choices, and this is going to last for ever…

Eventually I told Cordy that, yes, in her position I would be self-sacrificing and stay. Her response was an anguished groan. I felt sorry for her, and was about to take back my words-how did I know what I would do?-when she said, ‘I don’t think I can stay. But… only seeing Oonagh at weekends, it’s going to break my heart.’

Mine iced over as soon as I heard these words. ‘You mean… if you left you wouldn’t take Oonagh with you?’ I asked, trying to sound casual. And then it all came out: the ‘masterplan’. Cordy said that if she leaves Dermot she will let him keep Oonagh. ‘I couldn’t live with myself if I took her away from him,’ she said. ‘I mean, it’s not as if he can have more kids, is it? And it’s my fault. I’m the one who’s wrecking the marriage.’ She started crying then.

Cordy is not stupid. I’m sure she will succeed in fooling everybody apart from me. Her leaving-when it happens, as it undoubtedly will-will have nothing to do with this new man and everything to do with her being desperate to shake off her child, to be free again. People talk about being ‘tied down’ in the context of marriage, or living with somebody, but that’s rubbish. Before we had Lucy, Mark and I were entirely free.

The ingenious part is that no one will condemn Cordy for abandoning Oonagh. She will pretend she’s being self-sacrificing, putting Dermot’s needs before her own, heart-broken to be separated from her precious daughter.

‘I’m sure Dermot would still let me see Oonagh a lot,’ she sobbed. ‘She can stay with me every weekend, and in the holidays. Maybe we could even do fifty-fifty, and Oonagh could have two homes.’

‘A lot of men wouldn’t want to be the main one to look after a child,’ I told her, thinking of Mark, who would be hopeless. I don’t think he’s ever prepared a meal for Lucy. Or for anyone, come to think of it. ‘Are you sure Dermot does? Maybe he’d prefer Oonagh to live with you as long as he could have access whenever he wanted.’

Cordy said, ‘No, Dermot’s not like that. He’s a brilliant father. He’s done everything, right from the start. We’ve shared all the childcare, everything. I know he’d want Oonagh to stay with him.’

‘Right,’ I said, feeling my chest fill with white-hot envy. That was when I knew I wouldn’t be able to stand it. If Cordy escapes and starts a whole new life, if she manages to discard Oonagh and look like a saintly martyr in the process, I won’t ever be able to speak to her again.