‘I found out the truth. I heard your name by accident when I was in the editor’s office, and I knew straight away that it wasn’t Marlene she was excited about seeing. It was you. There was an old list of guests in the bin, so I read it to make sure that I hadn’t got it wrong, and there you were – you and the Hartleys. Alex kept all that from me, and I didn’t know why, so I confronted her with it when I got home. I asked her to take me with her, but she refused, and all those old insecurities came back. I was still the one left out in the cold, the one who wasn’t wanted. I’d always be the kid who was sent away, and suddenly that made me angry rather than sad. I told Alex that she owed it to me after what I’d done for her – one weekend didn’t seem too much to ask for saving her life. I wouldn’t let it go, and in the end she just turned round and screamed at me that she didn’t owe me anything because all I’d done was finish what she started.’ He closed his eyes and screwed his hands into fists, digging his nails into the palms of his hands to stave off the tears. ‘I couldn’t believe 271what she was saying at first, but then it all made sense. That’s why Ma turned on her – because of what she’d done to the others.’

That part did make sense, and although Penrose still recoiled from the idea that a twelve-year-old girl – a girl he had cared for – could be a murderer, he was experienced enough to know that history suggested otherwise. ‘Do you know why she did it?’ he asked, wanting at least an explanation if he had to accept the fact.

‘Because she found out that the family was going to be split up. Ma could only afford to take the little ones with her, and we were old enough to stay behind and work. She hadn’t told us everything because she didn’t want to spoil Christmas.’

Such a natural thing for a mother to do, Penrose thought: keeping a painful secret to protect the last Christmas they would share as a family. He tried to imagine the grief and horror that Mollie Naylor must have felt when she saw what her daughter had done, and realised why she had done it; had she been there to testify, he wondered if she would have thanked her young son for unwittingly putting her out of her misery. ‘People always said that violence was in our family,’ Naylor added. ‘My dad used to knock us around, so they thought it ran in the genes. Perhaps they were right, but they blamed the wrong kid – and Alex let them go on thinking it.’

‘And she destroyed your love for your mother,’ Penrose said. ‘You’ve spent your life hating her for things she hadn’t done, things she would never have done.’