The numbers have so many noughts as to be almost mind-bogglingly meaningless: 420,000 British casualties for the entire mess known as Somme, which dragged on until November 1916; 200,000 French and 500,000 Germans. That's over a million people killed, wounded or ill from trenchfoot, gas poisoning, tuberculosis, shell-shock.
All those men - and the women in the support services - woke up on this morning ninety years ago knowing they were about to be thrown into something momentous, purgatorial, unprecedented. But even they had no idea what was about to descend upon them. Imagine waking up that morning, in the dark - if you'd slept at all. Imagine crouching in a hole in the ground as the greatest artillery storm the world has ever known flies over your head - hopefully. Imagine climbing up out of the hole to greet the bullets.
I have a rendezvous with DeathAlan Seeger's rendezvous came on July 1. An American poet who had lived in Paris before the war and fought with the French Foreign Legion, he was 28.
At some disputed barricade,
When Spring comes back with rustling shade
And apple-blossoms fill the air...
Whole villages were effectively wiped out in minutes as the Pals Battalions, men all recruited from the same area, walked or ran or crawled into the machine guns. The haemorrhage didn't stop for another two years.
The end result was that the Allied front line moved forward six miles, ground lost later in the great German push of 1918.
I meant to be there, on the other side of the world today, but then remembered that battlefields are best visited alone. I went to Gallipoli alone. I certainly wouldn't want to be there with a million other people. And the stretch of countryside around Albert and Baupaume, the fields near Pozieres, the little towns and the memorials: for all of those I need time and solitude.
Half a world and a lifetime away, I feel like I know it already, that unconsecrated ground. I've spent years with my head wrapped in the Somme for a book I once wrote, that has never seemed quite finished or quite good enough.
But this morning, in the dark, I suddenly realised what's wrong with the manuscript and how to fix it, and had to get out of bed urgently and scribble. We all pay tribute in our own ways.