I stop, trying to locate the sound. I edge carefully towards a boggy area alongside the railway line.

‘Hello?’ I call out. ‘Is someone down there?’

‘I want Mummy!’

My head torch shines into the face of a small girl. Five or six, not bleeding from anywhere that I can see, but very pale.

She begins to cry properly now.

‘OK, sweetie, don’t cry. I’m here.’ I edge towards her. Seeing me will reassure her; plus, I can do a quick visual assessment before I radio for help. ‘We’ll soon get you out . . .’

One moment my feet are on the ground and the next I’m slipping, falling forward, towards the ditch . . .

I brace myself.

My shoulder hits the sodden earth first and I tumble as white-hot pain flashes through me. The exact same pain as when I fell out of the tree in Tim’s back garden—

It takes a second or two for the shock to subside, so I can make sense of what’s happened. OK: I am in freezing water up to my waist. As I move my arm, my eyes fill with tears. A fracture as well as a dislocation.

I reach down with my good arm, through the water, to pull out my radio. The display is dead. It can’t be. These are meant to be waterproof. Has it been damaged by the fall?

For a few seconds, I wait for a light: red, orange, green. Anything. But no. It’s gone.

My phone, then. It’s in the other pocket. Except as I twist to push my fingers between the folds of the fabric, there’s nothing there. Disbelief makes me try twice, three times, before I can accept it’s not there.

Think. The first thing I need to do is get to the girl. Someone up there will be looking for her. For us.

My head torch doesn’t give me any real sense of how far away she is and my useless arm is starting to hamper my progress, so I steel myself to try to reduce my shoulder. Dark pain swims over me as I push, hard, to get the ball back into the socket. I howl involuntarily.

The girl whimpers. At least I know she’s close by.

‘Shhh, it’s all right. I’m here. Tell me what you were doing today?’ I begin to crawl towards her voice and become aware for the first time that my ankle hurts too.

‘We’ve been . . . shopping . . . on the train.’

I don’t like the sound of her breathing.

‘Lovely. I’m nearly with you, it’s just this mud is so sticky. Tell me your name, sweetheart?’

‘Emily . . .’

‘And where do you live, Emily?’

She tries to tell me her full address, but I don’t catch all the words. I am almost alongside her, biting my lip as I crawl.