Canvas walls flapped in the wind off the Somme. Stretchers lined the duckboards in rows, most of them still.

Then the door banged open.

Two orderlies hauled a stretcher through, both breathing hard. The man on it was grey with dust, his uniform caked in yellow clay, and his chest heaved like a bellows.

His breath came in shallow, useless gasps. His fingers went to his own throat, as if trying to pull the air in himself.