Her little passenger fits perfectly in the car seat. It’s as though it was bought especially for her. See? It really was meant to be. But as soon as she has that thought, there’s a small whimper from the back seat.

‘I want Mummy now.’

‘We’ll see Mummy soon.’ Catriona prays she can cheer her up. ‘Have you eaten all your cookie?’

‘Yes. I want Mummy now. Mummy gets my juice.’

‘Are you thirsty, sweetie?’

‘Yes. I want juice.’

Sometimes Catriona keeps a bottle of water in the car. She throws a glance down at the passenger seat and into the door compartments, but there’s nothing there apart from an umbrella and some old receipts. ‘We won’t be long. Just ten minutes, all right?’ She glances in the rear-view mirror to see the girl’s little face grow red, her eyes bright with tears.

‘Shall I sing you a song?’

‘I want Mummy!’ the girl wails, working herself up.

Catriona feels like doing the same. But she has to stay calm. If she can just get them both home, get her little passenger a drink of water or juice and stop her tears, then she’ll work out what to do from there. She’ll just take this a moment at a time. If only the traffic wasn’t so heavy. If only the rain wasn’t so relentless and the sky so grey and dark.

‘G-g-get Mummy! Now! I want Mummy! I want MUMMY!’

Catriona grips the steering wheel hard, tries to steady her breathing. It will be okay. It will all be okay. She starts to hum a tune to herself. She doesn’t know what it is – a lullaby of some sort. To soothe the child and to soothe herself. But it can’t be heard over the yelling and sobbing from the back seat. The little girl is straining against the seatbelt, pulling at the straps. Leaning forward and then flinging herself back in her seat.

Catriona’s tuneless humming gradually turns into her own sobs. ‘Oh no, oh no,’ she wails over and over. ‘What have I done? What am I going to do? Please help me. Someone help me.’ If she’s not careful she’s going to crash the car and injure them both. She can’t do that. She has to calm down. Indicating left, she noses the car off the dual carriageway and down a slip road. A little further on she finds a layby. She pulls in, takes a breath, opens her door and dives through the pelting rain to the back door. She slips in and pulls the door shut, her hair now wet from just a few seconds outside. She should have pulled her hood back up. Never mind.

‘Hey, hey,’ she croons to the child. ‘What’s all this noise? What are all these tears for? Are you still thirsty?’

The girl sobs and nods. ‘Thirs-ty. Want Mu-ummy.’