Some years ago, an old German soldier, Henry Metelmann, told me the story of how he had killed his fatally wounded comrade on the Russian front.

Soldiers often become deeply attached to their mates in war, and Willi was Henry’s best mate. But in the freezing conditions of retreat across the Russian steppes, Willi was mortally wounded by a strafing aircraft and lay in the snow in appalling agony. Henry cradled his friend in his arms, and quickly and expertly put a bullet through his heart. He then gave him as respectful a burial as he could, before being summoned to move on.