Giles winced. ‘No – you’re right. There is a doubt – but it seems more like a certainty. When did it first occur to you?’

‘From the moment I first saw him, of course. I’m not stupid. It’s just so obvious. Dad . . . did you . . . were you. . . you must have known about it before he came?’

‘I’d . . . wondered.’ Giles paused miserably, not sure how much to tell Amy. Then he said: ‘I was afraid it was a possibility. By the time we discovered your aunt was pregnant she’d left her flat In Edinburgh and decided to go back to South Africa – that was a surprise in itself – but I desperately needed to know. I flew down to London to see her just before she left and confronted her. She denied, point blank, that I was the father.’

‘Did Mum know that?’

‘Not before I went. I told her when I came back.’

‘And you believed Aunt Lorna?’

Giles hesitated. Then he said: ‘I very much wanted to believe her – not least for your mother’s sake – but Lorna has always bent the truth so I admit I wasn’t entirely convinced – but I wouldn’t have been convinced if she’d said the baby was mine either. Then when we heard from your grandparents that the baby had been born it was easy to accept – because either the baby was premature or the dates didn’t quite fit.’

Amy twisted the ropes of the swing, and slowly spun round as she let them unwind. Then she said: ‘It was that awful Suzuki weekend that went so wrong for me, wasn’t it? When Mum didn’t come with us and you took Aunt Lorna in her place?’

‘Yes,’ said Giles. ‘It was then. I made a huge mistake.’

‘Mistake?’ Amy snorted scornfully.

Giles knew he must keep a hold on his temper and not be goaded into attempting justifications or discussing Lorna’s devious tactics. Above all he must resist the temptation to mention Isobel and Daniel Hoffman. He said, ‘All right, Amy – you have every reason to be angry. I behaved very badly. I’m not excusing myself but I’d like you to know that it only occurred once and I immediately made it plain to Lorna it must never happen again. And it never did – though not for want of her trying.’

‘I hate her,’ said Amy. ‘I really hate her. How could she do that to Mum?’