But that relies on one huge assumption: that the police will listen, believe him, and act in a matter of minutes to stop the bus before it reaches the level crossing. Will they do that? There’s no guarantee, that’s for sure. Running back to school, away from this impending disaster, it feels wrong.

Will stops for a second. How long has he got now? Twenty minutes at a push. No more than that.

The number 83 takes a tortuous diagonal path through Ebbswick, stopping every four hundred metres. The route it follows is far from the quickest way to reach the sea. He might not be able to catch the bus, Will knows, but that doesn’t mean he can’t get to the level crossing first. If he can do that, perhaps he can stop it before it pulls over the tracks.

The key is to make this journey as the crow flies. And that means not going through Ebbswick at all, but through the industrial estate on the outskirts of town and, from there, cross-country over the marshes. He’ll reach the railway parallel to the shore. From there it’s maybe eight hundred metres along the tracks to the level crossing.

How far is it? A good five-mile ride on the bus. But the route Will’s planning can’t be more than half that. Can he make it? Four kilometres in under twenty minutes? It should be doable. Right now, it’s the best option.

The snow has become a blizzard. The landscape is utterly silent as Will sprints down a single-track lane. His vision is filled with the fuzz of snowflakes rushing into his face. Even his footfalls are muted; the only sound is his own heavy breathing folding back from the icy cocoon around him. Water runs down his arms, warm and crimson by the time it runs off his wrecked knuckles.

His feet skid across the ground as he reaches a left turn into a bridleway. He reaches out and grabs the rusted signpost that points to the industrial park and seafront, pivoting round it and launching himself downhill. Twice, he trips, but he loses no momentum, hands clawing along the rutted ground until he’s able to right himself.

‘Please. Please,’ he repeats as he runs. ‘Please let me make it.’

Every few minutes, he feels the onset of fatigue, of muscles crying enough. And then he visualizes them, the children, bent and broken, dead in the snow. And all those people on the train who’ll never make it home. And he runs even faster.

The bridleway opens out on to a sweeping crescent-shaped road. It’s lined with tall steel fences and gates secured by chains. Beyond, there are flat-roofed industrial units: a builders’ merchant’s, a tyre depot, a haulage firm. Will follows the line of the fence. Somewhere here there’s an alley that cuts through the estate and on to the marshes beyond.