‘Can you remember exactly what she said?’ Perez struggled to imagine the conversation between the two women. They’d be seated across the table from each other picking at plates of spicy food. A glass of wine each perhaps. And they’d be batting words back and forth, a peculiar game of verbal ping-pong. Eleanor must have wanted something from the meeting. She’d be busy, if it was the day before she set off for Shetland. What had been so important that she’d insisted on seeing her mother for lunch?

Cilla frowned. ‘She said that she was setting off on a great adventure and asked if I planned anything similar myself. Clearly she wanted me to ask what she meant, but I pretended not to understand. I told her that Shetland was a long way north, but it was hardly a journey of a lifetime. After all she’s used to foreign travel. I used to take her with me on field trips.’

‘And what do you think she meant?’

‘Well, not a long drive and an overnight ferry,’ Cilla said. ‘Clearly the adventure she spoke of was more metaphorical than geographical.’

Perez thought there was nothing clear about the communication between the mother and daughter. Their relationship seemed to involve a strange game of second-guessing and pretence. ‘Could you be more specific?’

‘It might have been a new man, I suppose,’ the woman said. ‘That would be the most prosaic explanation. Or a spiritual journey. She was very lit up. Perhaps she’d even started to believe in her ghosts. Or it could just have been her work. In the end that was always what meant most to her.’ She stood up. ‘We said goodbye on the pavement and she hugged me. She was always very touchy-feely with her friends, but never with me, so I was taken aback by that. Then she walked away. I nearly called her back. I had the words in my head. What was that all about, Nell? What did you really want from me? But then I thought about my project at the museum and how I was already behind schedule. I stood for a moment and watched her climb into a cab. And then I went back to work.’

They looked at each other. Perez got to his feet too. He knew that was what was expected of him. ‘What time did she leave you?’

‘I’m not sure. About two-thirty.’

So what had Eleanor done between having lunch with her mother and meeting Polly in the library in Hampstead? Had she gone back to the office?

Cilla was looking at him impatiently, but he stood his ground.

‘Did Eleanor get in touch when she was in Shetland?’