The doorbell rang. ‘I’ll get it,’ I said, wiping my hands hurriedly on a tea towel. An elderly lady stood before me at the door in a red coat and a beret. She asked me if Mrs B was in, and I told her that I didn’t know a Mrs B, we were the new owners.

‘Oh.’ She looked stunned. ‘Have they moved?’ Her eyes flitted towards the window, and then she said. ‘Their curtains are still up, so I thought……’ She trailed off, looked at her feet, and I felt a bit sorry for her. ‘Well, they might’ve told me they were moving. She IS my sister,’ she complained, adjusting her black crossover bag and pursing her lips. I shook my head, agreed, apologised for her disappointment. How could her sister jut take off without telling her? Perhaps they’d fallen out, I thought. Sibling rivalry is common, but to actually move and not tell your sister. I told her the curtains were only temporary. We were decorating, hadn’t moved in yet, and she thanked me, apologised for disturbing me and went on her way.

Half an hour later there was another knock at the door. I saw her red coat and mop of white hair sprouting beneath her beret through the obscure glass. ‘Hello, is Mrs B in?’

Two years later, the doorbell rang. Mary asked me if her sister was in, even though we’d changed the curtains. We talked about her sister selling up and moving, even though I knew her sister had died 20 years ago.

‘Do you want me to walk you home, Amy?’

‘Yes, please,’ she smiled, a little embarrassed. ‘I’ve forgotten where I Iive.’

And I walked her to her house up the road, told her to stay in, said it was getting dark now, cold, and she promised that she would.

I walked her home about two or three times a week. Then one day she stopped coming. But I still think of her whenever I walk past her house and smile.

You can find out more about Alzheimer’s disease and Dementia, including ways of how you can help, by visitng Alzheimer’s Society