From the car she’d phoned the archivist, Simon Barr. He’d heard of the Sentiman Library, shared her fascination with folk tales and agreed to see her at once. She found him upstairs in a big, open-plan office, with a view of the Hay’s Dock. She decided this constant presence of water was adding to her unease. She’d never learned to swim and as a child she’d had nightmares about drowning. She hadn’t thought about the dream for years, but since Eleanor’s death it had recurred, just as she was waking, so it stayed with her all day. Now she pictured the sea eating away at the islands, nibbling them piece by piece until there was no land left and the water overwhelmed her. She sat with her back to the window facing Barr’s desk.

‘So you want to know about our Peerie Lizzie,’ he said. ‘Of course it’s quite a recent legend, as these things go. My grandmother worked at Springfield House when she was a girl, though she’s been dead for many years now.’

‘Did she tell you what happened the day Elizabeth was drowned?’

‘She told me her version of the story, but I couldn’t say how much was true and how much she’d made up over the years. She was full of tales and, like a lot of old people, she mixed up the fact and the fiction in her mind, I think.’

‘Did she believe in the ghost?’ Polly found that she was holding her breath.

‘Oh, she claimed to have seen her. She spent all her life in Unst. Before its present owners took it on, Springfield House was empty for years and local folk treated the land as their own, taking their children to picnic in the gardens. According to my grandmother, Lizzie appeared to her when she was picking raspberries there one summer. It was late in the evening and she was on her own. The child was dressed in white and seemed to walk towards her in the walled garden; then she disappeared although the gate was shut.’ He paused and grinned. ‘But don’t believe a word of it. As I told you, my grandmother loved making up stories.’

‘What did she tell you about the child’s death?’

‘She said everyone blamed Sarah Malcolmson, but it wasn’t really her fault. She’d been given the day off to help her mother with a new baby, and she was only there when Elizabeth ran down to the shore because she’d stopped to chat to the lad who worked in the gardens on her way home. If anyone was responsible for the accident it was Lizzie’s mother, Roberta.’

‘Are there any reports into the accident?’