Then she saw it: a gap in a row of five matching framed photographs. Now there were four. The first, a picture of Ned, her late husband, grinning broadly and leaning against the bonnet of his precious MGB Roadster. Second, their wedding day. Next, Andrew, taken just before he left to start his basic training with the RAF. Then the gap, and finally her mum and dad on their ruby wedding anniversary.

Annie stared at the space and her mouth went dry. The missing picture was of Callum.

She walked slowly back to the kitchen, cursing herself for not calling the police immediately. But in the absence of any actual harm and with nothing missing, what was there to say? More than likely they wouldn’t even send anyone out. This was a small Fen village, and she hadn’t seen a police officer in years. She wasn’t even certain where the nearest police station was anymore, they had closed so many. But that missing photograph changed everything.

‘I think you should try to get some sleep, sweetheart. It’s four in the morning and you’ve got school tomorrow.’ She tried to sound casual. ‘Take your drink upstairs, I’ll come up with you.’

‘Are you coming to bed, Mum?’ He clearly hadn’t been totally reassured by their hurried patrol through the house.

‘In a little while. I should ring the police. He could be going around bothering other people.’ She tried to keep it light.

He nodded. ‘Yeah. Good.’

She followed him up the stairs. ‘I’ll leave your door open. I’ve already checked — the windows are closed and the doors all locked, so he won’t come back now. Try to sleep.’ He climbed into bed and took his phone and his earbuds from the bedside cabinet. ‘I’ll call in when I go to bed, okay?’

He was already scrolling through his playlist. The music would help.

‘I’m leaving the light on,’ he stated firmly.

She stuck a thumb up and winked, like his father used to do, and hurried back down the stairs.

In the kitchen, she picked up the phone and dialled. ‘Police, please. Someone broke into my house, got into my bedroom and stole a picture of my son. We’re on our own here, and we’re scared.’

She had expected to be given an incident number, fobbed off with an excuse about shortages of personnel, so she was taken aback when she was told that a car from Saltern-le-Fen would be on its way immediately.

Thirty minutes later a marked police car pulled up outside. Even so, she waited until she saw the uniforms.

The two PCs introduced themselves as Stacey Smith and Jay Acharya. They were quick to assure her that she had done the right thing in calling them. Handing them mugs of tea, she began to describe waking up and seeing that silent figure staring down at her. At that point, the shock overwhelmed her and she burst into tears.

‘It’s okay, it’s okay.’ PC Smith handed her a tissue and sat down next to her on the sofa. ‘It’s delayed shock, Mrs Carson, don’t worry. It’s a good thing it’s coming out.’