The nurse made a helpless gesture. ‘The doctors . . .’

‘Livy?’ I stood up and approached her, feeling an irrational wariness as if she were charged and I might be electrocuted if I touched her.

‘She’s at the end of the treatment now,’ the nurse was saying. ‘She’s had two courses. There won’t be any more – not for a while.’ Her eyes flickered back and forth to the door.

I drew up a chair and placed it next to Olivia’s. She sat staring ahead of her with no expression, looking completely exhausted. I reached out and took her undamaged hand. ‘Darling? It’s Katie.’

I felt I could not reach her. She looked so strange, so impassive and resigned. They could do to her what they wished.

‘You do know who I am, don’t you?’ I asked, frightened.

She gave a very slight nod.

‘She’s ever so tired,’ the nurse said. ‘She’ll get better. It can affect their memory for a little while.’ I knew the nurse had a special bond with Olivia and felt protective towards her. She gave me a sudden smile, sympathetic and wistful.

‘Livy,’ I implored, almost sobbing. ‘What is all this about? It’s been so long now – can’t you tell me why you’re so sad?’

I thought there was going to be no response. She was shivering in the huge, echoing room, wearing the gingham dress again, and so far as I could see she had no other garments. I embraced her bony shoulders. ‘Oh Livy, I love you.’ Helplessly I sat and cried, and she remained like stone in my arms.

But she turned to me then, gave me that strange, searching look of hers and said, ‘The baby.’ And went limp as if the words had been a rod in her spine. She folded her arms across her and began to rock, her voice tiny and plaintive.

‘My baby, my baby. My little baby.’ She was cradling the plaster cast as if it was a child, and this looked such a classic pose of madness that for a moment I wanted to seize hold of her and make her sit still. I glanced anxiously at the nurse. She met my eyes for a second, then moved her gaze deliberately to the high windows, light falling on her face.

‘He was mine for one night,’ Olivia was saying. ‘Mine. He drank my milk and I held his little hands. In the morning they took him away from me.’

I struggled to make sense of what she was saying, wondering if all this was some kind of delusion. ‘When?’ I asked softly.

‘He was born on October 15th, 1941. On October 16th they took him away from me.’ She recited this woodenly, staring away from me across the room.

Things started to make terrible sense. ‘But they said you had pneumonia!’

‘Of course. They wouldn’t tell you the truth, would they? My bastard baby. And now he’s punishing me.’ The high, babyish voice came back. ‘It was my fault. It always was my fault. I’m filthy. I asked for it.’