Mr Stone, who went on to serve in the Royal Navy in both World Wars, is due to give a reading shortly after Big Ben chimes 11am. Alongside him will be Henry Allingham, Britain’s oldest war veteran. He turned 108 two months ago, on the very day that those young pups, the Normandy veterans, were marking the 60th anniversary of D-Day.

He was yet another excited young man on August 4, 1914. Already obsessed with motorbikes, he saw the war as an opportunity to ride a racier model and immediately tried to enlist as a dispatch rider at a London recruiting office.

But the Royal Engineers had enough riders already and Mr Allingham’s widowed mother was unwell. So he remained at home until her death the following year when he promptly entered the Royal Naval Air Service.

The fourth member of this morning’s gallant quartet will be Jack Oborne, who was a 14-year-old apprentice carpenter on the day that war broke out.

It would be another three years before he put on a uniform, although he would still have more than enough time to experience the very worst that the Western Front had to offer.

This morning may be the anniversary of the day it all began. But August 4, 1914, will not be uppermost in the minds of these men. As a bugler sounds the Last Post, they will be remembering what happened next.

Fred Lloyd, the youngest of 16 orphaned children, wanted to follow his three older brothers into the Army but was turned down by the local Sussex Regiment for being too short. He was, though, allowed to join the Royal Artillery to look after the horses which were still vital to trench warfare. Despite an attack of meningitis which nearly killed him, Private Lloyd made it out to northern France, where it was his task to take fresh horses up to the line and bring the sick ones back. To this day, he is baffled by the number which lost their sight. “Hundreds of horses went blind in that war, but I don’t think anyone ever worked out why that was.”

He remains very reluctant to discuss the sights he saw, so much so that he has never even shared them with his family. “He opened up to me once about it, telling me how everything from thoroughbreds to old nags were just blown to pieces. But it made him very distressed,” says Dee Johnson, who looks after Mr Lloyd at the Thornbury Residential Home in East Sussex.

Of his three brothers, one was killed at Arras, one died at the Somme and the third returned home with shrapnel in his head. Mr Lloyd still regards himself as one of the lucky ones.

So, too, does Mr Stone. “Every day, I think what a bloody lucky man I am to be here,” he tells me from the Oxfordshire home where he still lives alone, doing his daily exercises with his chest-expanders and handgrips: “I’ve got such a strong handshake, people won’t shake hands with me.”

By the time he joined the Royal Navy, the war was nearly over, although he still remembers seeing the German fleet scuttled at Scapa Flow. But if his youth was an asset in the First World War, it did him no favours when the Second broke out.

Just as he should have been retiring, he was sent back to sea in 1940. He made five desperate trips to Dunkirk, watching his sister ship and her cargo of fleeing soldiers blown to pieces. Chief Petty Officer Stone was mentioned in dispatches after his ship was torpedoed off Sicily in 1943 and endured the horrors of the Russian convoys.

And still, he cannot believe his good fortune. “I survived the first war, then the influenza which killed even more people, then the second war. That’s why I trust in God.”