SOME DAYS I don’t remember my mother. I look at her photograph and she escapes me. Or I see her on a Sunday, after lunch, and we spend a pleasant afternoon, and when I leave I find she has run through me like water.

‘Goodbye,’ she says, already fading. ‘Goodbye my darling girl,’ and she reaches her soft old face up, for a kiss. It still puts me in such a rage. The way, when I turn away, she seems to disappear, and when I look, I see only the edges. I think I would pass her in the street, if she ever bought a different coat. If my mother committed a crime there would be no witnesses-she is forgetfulness itself.

‘Where’s my purse?’ she used to say when we were children-or it might be her keys, or her glasses. ‘Did anyone see my purse?’ becoming, for those few seconds, nearly there, as she went from hall, to sitting room, to kitchen and back again. Even then we did not look at her but everywhere else: she was an agitation behind us, a kind of collective guilt, as we cast about the room, knowing that our eyes would slip over the purse, which was brown and fat, even if it was quite clearly there.

Then Bea would find it. There is always one child who is able, not just to look, but also to see. The quiet one.

‘Thank you. Darling.’

To be fair, my mother is such a vague person, it is possible she can’t even see herself. It is possible that she trails her fingertip over a line of girls in an old photograph and can not tell herself apart. And, of all her children, I am the one who looks most like her own mother, my grandmother Ada. It must be confusing.

‘Oh hello,’ she said as she opened the hall door, the day I heard about Liam.