The final entry on the form is dated 12th October 1916 and  bears a stamp for ‘Wounded in Action’. Beneath it is written by hand: ‘S.[hell] W.[ound] Chest and Abdomen. Died 5:30 am.’ He was nineteen.

I imagine the news being brought – by bicycle? – to the little shop on Moyser Road. I can guess at the habits of faith and stoicism being stretched and tested by the shock. For some reason, I see his father wearing a black armband, manfully accepting the condolences of his customers. I expect Leonard Senior was present in 1920 at the dedication of the parish war memorial: fifty-three names from half a dozen streets. Did he look around at the other bereaved parents? Was the early rawness of their grief calloused a little with time? What on earth did they say to one another?

Some version of that loss reverberated through my grandfather’s life for close to a century. It was still present in the timbre of his voice, seventy years on: he was a good bloke. That laconic epitaph contained as much grief as he ever allowed himself. It was a family trait never to revisit the past.

Leonard’s death closed off a whole branch of possibilities for people who never knew him. Each of those names on the memorial expunged an alternate future. The hundreds of thousands of absent men left a whole generation of women without their future partners.

And, unthinkable as it seems, maybe Leonard took lives; maybe he was a killer, setting off a chain of absences on the other side.

The fiction of a nation is invariably written with the blood of young men: Thermopylae, Masada, Kosovo, Crécy, Culloden, Gettysburg, Gallipoli, Stalingrad. The unspeakable things that happened in these places become the totem  that defines a tribe. But in every story that sings of feats of arms, heroism, noble sacrifices, there’s a voice that whispers something else, that insists that all that’s real is young men getting chewed up in a bloody accident.

I say that not as a pacifist. The haruspex in me can invent circumstances where I’m compelled to give or take a life. I hope I’ll be able to face my own death with the appropriate gravity and courage. I hope I’ll remember that death is less often a tragedy, more often another regrettable fact.

But it’s one thing to imagine your own death – brief, one hopes, as the shock of immersion in freezing water. It’s quite another to imagine your child – or a whole generation of children – out there in the darkness, mortally wounded, dying alone.

You can’t help wondering about the world where this didn’t happen, a world without Sarajevo, where the dead of Passchendaele never left home, a France unhaunted by the mutilated gueules cassées, where the Anzac regiments never embarked, where Leonard took over the shop on Moyser Road and married a girl from the Baptist Church. What would that world have been like? We can’t know, of course; but it would say in the secret books.