Eventually a kind teacher noticed them still there and asked if they were all right; did they want her to phone Mum to see what was going on? Olivia had felt embarrassed – she’d been a shy child and hated being singled out for any kind of attention, and so she mumbled an excuse, before grabbing Danny’s hand and making a brisk exit. She was ten, she knew the way home and was sensible about crossing roads, although Danny had whined all the way back about wanting a lolly, until Olivia had felt like slapping him.

It was only when they arrived home to find the house empty, and nobody answering the door, that Olivia felt the first pricklings of fear. She could remember even now the hollow feeling in her stomach as she’d knocked and knocked, then pressed her finger to the bell in a long loud DRRRRRRRRING. Something had dropped away inside her stomach, a hot, loose sensation of uncertainty. Mum wasn’t there. Nobody was there.

After a short while they’d gone round to the back and peered hopelessly into the kitchen window, but still there was no sign of Mum. Alarm started to punch holes in her and a bad feeling poured in – the conviction that she must have done something wrong, that this was her fault. She and Danny had sat there, shivering like two little orphans on the back step, for nearly two hours as the freezing darkness gathered like clouds of ink around them, until Olivia’s dad had finally come home from work and found them.

Nothing had ever been the same, after that. The family had broken, never to be fully repaired. There had been no reconciliation, no attempts to explain or reunite. Nothing at Christmas or birthdays – not a word. Rumour had it that Sylvia had moved to Redruth, there were sightings now and then, according to the neighbours’ gossip, but it might as well have been the moon. The police added her name to the register of missing persons, but said there was nothing else they could do. Was she alive? Was she dead? She had simply gone and not come back.

It was the waiting that was the worst. The gradual crumbling away of hope, year after year. Olivia’s dad was angry and drunk for a while, and his Devonshire parents came to look after the children and the house, as their son fell apart before their eyes. Within two years he had pulled himself together and married again, though: to Gail, a quiet owlish sort of woman, who didn’t like to have Sylvia’s name mentioned in the house. Olivia couldn’t give up so easily and, with the advent of the Internet, continued to search for her mother, a sighting, a reference. Nothing. It was like an ache inside. A hole that could never be filled.