Bert lost his temper and pulled Joseph out of the toilet. When they were at the top of the stairs, Joseph started swearing at his father, using such words I’ve never heard before and would blush to repeat. That’s when Bert lost his temper and hit him. On God’s honour, he didn’t mean to hurt him. Joseph was our only son and we loved him even though he was breaking my heart. But when Bert hit him Joseph fell down the stairs and when he got to the bottom his head was at such a funny angle I knew he must have broken his neck.

The girl started screaming then took the baby and ran outside and drove away. We have never seen her again or our grandson and don’t know what has become of him. There was such a silence like you have never heard when the sound of the car engine vanished in the distance and Joseph was laying at the bottom of the stairs all twisted and broken. We tried to feel his pulse and Bert even put a mirror to his mouth to see if his breath would mist it but there was nothing.

I know we should have told the truth and we have regretted it for all those years. We were always brought up to be decent honest folk respecting our parents and God and the law. Bert was ashamed that his son was a drug addict and didn’t want it in the papers. I didn’t want him to go to jail for what he had done because it was really an accident and it wasn’t fair. He was suffering more than enough anyway because he had killed his only son.

So I said we must throw away all the drugs and needle and things and take our Joseph’s shoes off and say he slipped coming down the stairs. We knew that the police would believe us because we were good people and we had no reason to lie. That was the hardest part. The laces got tied in knots and I broke my fingernails and in the end I was shaking so much I had to use the scissors.

And that is God’s honest truth, Mr Banks. I know we did wrong but Bert was never the same after. Not a day went by when he didn’t cry about what he’d done and I never saw him smile ever again. To this day we still do not know what has become of our grandson but whatever it is we hope he is healthy and happy and not as foolish as his father.

By the time you read this letter I’ll be gone to my resting place too. For two years now I have had cancer and no matter what operations they do it is eating me away. I have saved my tablets. Now that I have taken the weight off my conscience I can only hope that the good Lord sees fit to forgive me my sins and take me unto his bosom.

Yours sincerely,

Betty Atherton

Banks put the letter aside and rubbed his left eye with the back of his hand. Outside, the rain was still falling, providing a gentle background for Finzi’s Clarinet Concerto on the portable cassette. Banks stared at the sheets of blue vellum covered in Betty Atherton’s crabbed hand, then he cursed, slammed his fist on the desk, went to the door and shouted for Susan Gay.

‘Her name is Catherine Anne Singer,’ said Susan the next afternoon. ‘And she was relieved to talk to me as soon as I told her we weren’t after her for leaving the scene of a crime. She comes from somewhere called Garden Grove, California. Like a lot of young Americans, she came over to “do” Europe in the sixties.’

The three of them – Banks, Susan and Jenny Fuller – sat over drinks at a dimpled, copper-topped table in the Queen’s Arms listening to the summer rain tap against the diamonds of coloured glass.

‘And she’s Jerry Singer’s mother?’ Banks asked.

Susan nodded. ‘Yes. I just asked him for her telephone number. I didn’t tell him why I wanted it.’

Banks nodded. ‘Good. Go on.’

‘Well, she ended up living in London. It was easy enough to get jobs that paid under the counter, places where nobody asked too many questions. Eventually, she hooked up with Joseph Atherton and they lived together in a bedsit in Notting Hill. Joseph fancied himself as a musician then-’

‘Who didn’t?’ said Banks. He remembered taking a few abortive guitar lessons himself. ‘Sorry. Go on.’

‘There’s not a lot to add, sir. She got pregnant, wouldn’t agree to an abortion, though apparently Joseph tried to persuade her. She named the child Jerry, after some guitarist Joseph liked called Jerry Garcia. Luckily for Jerry, Annie wasn’t on heroin. She drew the line at hash and LSD. Anyway, they were off to join some Buddhist commune in the wilds of Scotland when Joseph said they should drop in on his parents on the way and try to get some money. She didn’t like the idea, but she went along with it anyway.

‘Everything happened exactly as Mrs Atherton described it. Annie got scared and ran away. When she got back to London, she decided it was time to go home. She sold the car and took out all her savings from the bank, then she got the first flight she could and settled back in California. She went to university and ended up working as a marine biologist in San Diego. She never married, and she never mentioned her time in England, or that night at the Atherton farm, to Jerry. She told him his father had left them when Jerry was still a baby. He was only two and a half at the time of Atherton’s death, and as far as he was concerned he had spent his entire life in southern California.’

Banks drained his pint and looked at Jenny.

‘Cryptomnesia,’ she said.

‘Come again?’

‘Cryptomnesia. It means memories you’re not consciously aware of, a memory of an incident in your own life that you’ve forgotten. Jerry Singer was present when his grandfather knocked his father down the stairs, but as far as he was concerned consciously, he’d never been to Swainsdale before, so how could he remember it? When he got mixed up in the New Age scene, these memories he didn’t know he had started to seem like some sort of proof of reincarnation.’

Sometimes, Banks thought to himself, things are better left alone. The thought surprised him because it went against the grain of both his job and his innate curiosity. But what good had come from Jerry Singer presenting himself at the station three days ago? None at all. Perhaps the only blessing in the whole affair was that Betty Atherton had passed away peacefully, as she had intended, in her pill-induced sleep. Now she wouldn’t suffer any more in this world. And if there were a God, Banks thought, he surely couldn’t be such a bastard as to let her suffer in the next one, either.

‘Sir?’

‘Sorry, Susan, I was miles away.’

‘I asked who was going to tell him. You or me?’

‘I’ll do it,’ said Banks, with a sigh. ‘It’s no good trying to sit on it all now. But I need another pint first. My shout.’

As he stood up to go to the bar, the door opened and Jerry Singer walked in. He spotted them at once and walked over. He had that strange naive, intense look in his eyes. Banks instinctively reached for his cigarettes.

‘They told me you were here,’ Singer said awkwardly, pointing back through the door towards the Tudor-fronted police station across the street. ‘I’m leaving for home tomorrow and I was just wondering if you’d found anything out yet?’