She nodded. ‘I know. And I now know that it wasn’t him.’

‘How?’

‘I told Liv about it at work. Her two boys are older than Logan but I wondered whether either of them had done anything similar, thinking maybe it was a phase that little boys went through. Anyway, she reminded me that I’d spotted her at the bus stop the night I missed the bank. Her bus hadn’t turned up and it had started raining so I offered her a lift home. The fuel light came on so I stopped off at Sainsbury’s to fill up because it’s on the way to Liv’s. I realised I’d left my purse at Bear With Me, but it didn’t matter because I had the banking with me.’

‘And you put £50 of petrol in the car?’ I tried not to sound angry with her as I said it, but I felt pretty aggrieved on behalf of my poor little brother, being accused of stealing so much money.

‘Yes. I still had the receipt in my bag with the banking.’

‘What about the sleepover and trips?’

‘It turns out I paid by cheque. I found the stubs in my cheque book.’

‘Oh, Mum! When was this?’

‘Middle of last week. I told Logan the truth, of course, and apologised to him, but I think he’s still sulking. I can’t say I blame him.’ She looked up again, biting her lip. ‘I shouted, Jemma. Really shouted. I didn’t recognise myself.’

I nodded slowly as I let the information sink in. I couldn’t recall a single occasion when I’d heard Mum shout. She’d never raised her voice when I was a child, not even when I’d cut up an expensive piece of her bear-making mohair because I thought it would make nice rugs for my Barbie house. She’d argued with Dad, but I’d never heard her shout at him and he’d certainly given her just cause over the years, especially when it came to his attitude towards Logan.

‘What sort of day had you been having?’ I asked.

‘Not a good one, but not the worst. Definitely not the worst. I don’t know what happened. I don’t know why I forgot about spending the money myself, or paying for the trips by cheque, and I don’t know what made me accuse my baby boy of stealing.’

‘Mum, I hate to say this, but do you think there could be something else? Other than the Parkinson’s, I mean.’

She frowned. ‘I’m not with you.’

‘Making you forget things. Could it be…?’ I paused. I couldn’t bring myself to say the word that had been haunting me since that evening in the hot tub when Mum had talked about the lido. ‘I don’t know. A side effect maybe? Could it be worth mentioning something to Dr Steadman next time you see him?’