Dad had told me over the phone that she had left Granta House within weeks of Will’s death. He said the estate workers had been shocked, but I thought back to the time I had spotted Mr Traynor out with Della, the woman he was now about to have a baby with, and I wondered how many genuinely had been. There were few secrets in a small town.

‘She took it all terrible hard,’ Dad said. ‘And once she was gone your redheaded woman there was in like Flynn. She saw her chance, all right. Nice auld fella, own hair, big house, he’s not going to be single for long, eh? Speaking of which, Lou. You – you wouldn’t have a word with your mother about her armpits, would you? She’s going to be after plaiting it if she lets it all grow any longer.’

I kept thinking about Mrs Traynor, trying to imagine how she would react to the news about Lily. I remembered the joy and disbelief on Mr Traynor’s face at their first meeting. Would Lily help to heal her pain a little? Sometimes I watched Lily laughing at something on television, or simply gazing steadily out of the window lost in thought, and I saw Will so clearly in her features – the precise angles of her nose, those almost Slavic cheekbones – that I forgot to breathe. (At this point she would usually grumble, ‘Stop staring at me like a weirdo, Clark. You’re freaking me out.’)

Lily had come to stay for two weeks. Tanya Houghton-Miller had called to say they were off on a family holiday to Tuscany and Lily didn’t want to go with them. ‘Frankly, the way she’s behaving right now, as far as I’m concerned, that’s fine. She’s exhausting me.’

I pointed out that, given Lily was barely at home, and Tanya had changed the locks to her front door, it would be pretty hard for Lily to exhaust anyone unless she was tapping at their window and singing a lament. There was a short silence.

‘When you have your own children, Louisa, you might eventually have some idea what I’m talking about.’ Oh, the trump card of all parents. How could I possibly understand?

She offered me money to cover Lily’s board and lodging while they were away. I took some pleasure in telling her I wouldn’t dream of taking it, even though, frankly, it was costing me more than I had anticipated to have her there. Lily, it turned out, wasn’t satisfied with my beans-on-toast or cheese-sandwich suppers. She would ask for cash, then return with artisan bread, exotic fruit, Greek yoghurt, organic chicken – the staples of a wealthy middle-class kitchen. I remembered Tanya’s house, the way Lily had stood by the oversized fridge and thoughtlessly dropped chunks of fresh pineapple into her mouth.

‘By the way,’ I said, ‘who is Martin?’

There was a short pause. ‘Martin is my former partner. Lily apparently insists on seeing him, even though she knows I don’t like it.’

‘Could I have his number? I’d just like to make sure I know where she is. You know, while you’re gone.’

‘Martin’s number? Why would I have Martin’s number?’ she squawked, and the phone went dead.

Something had changed since I’d met Lily. It wasn’t just that I’d learned to accommodate the explosion of teenage-related mess in my near-empty flat, I had actually started to quite enjoy having Lily in my life, having someone to eat with, sit side by side with on the sofa, commenting on whatever we happened to be watching on the television, or keeping a poker face when she offered me some concoction she’d made. Well, how should I know you have to cook the potatoes in a potato salad? It’s a salad, for God’s sake.

At work I now listened to the fathers at the bar wishing their children goodnight as they flew off on business trips – You be good for Mummy now, Luke … Did you? … You did? Aren’t you a clever boy! – and the custody arguments conducted in hissed telephone conversations: No, I did not say I could pick him up from school that day. I was always due in Barcelona … Yes, I was … No, no, you just don’t listen.

I couldn’t believe that you could give birth to someone, love them, nurture them, and by their sixteenth year claim that you were so exasperated that you’d change the locks of your house against them. Sixteen was still a child, surely. For all her posturing, I could see the child in Lily. It was there in the excitements and sudden enthusiasms. It was there in the sulks, the trying on of different looks in front of my bathroom mirror and the abrupt, innocent sleep.

I thought of my sister and her uncomplicated love for Thom. I thought of my parents, encouraging, worrying about and supporting Treena and me, even though we were both well into adulthood. And in those moments I felt Will’s absence in Lily’s life like I felt it in my own. You should have been here, Will, I told him silently. It was you she really needed.

I booked a day’s holiday – an outrage, according to Richard. (‘You’ve only been back five weeks. I really don’t see why you need to disappear again.’) I smiled, bobbed a curtsy in a grateful Irish-dancing-girl manner, and drove home later to find Lily painting one of the spare-room walls a particularly vivid shade of jade green. ‘You said you wanted it brightening up,’ she said, as I stood with my mouth open. ‘Don’t worry. I paid for the paint myself.’

‘Well,’ I pulled off my wig, and unlaced my shoes, ‘just make sure you’ve finished by this evening because I’ve got the day off tomorrow,’ I said, when I had changed into my jeans, ‘and I’m going to show you some of the things your dad liked.’