As the horses charged over the hill, it was like the Battle of Waterloo On Monday I was a guest at Chelsea Barracks, alongside assorted civilians, a clutch of seasoned army wives and some jocular top brass, all assembled to watch the King's Troop Royal Horse Artillery (KTRHA) deliver a Royal Salute in honour of the Duke of Edinburgh's 92nd birthday. Now, I must have seen the term "Royal Salute" a thousand times, as in "a Royal Salute was fired to mark the Queen's birthday," or "to welcome President Obama." Yet I have never properly pondered who delivers that tribute. I have lived in sad ignorance of the glorious military machinery that swings into place to deliver, on behalf of the nation, a thrilling tribute to the monarchy, visiting dignitaries and our great state institutions. It's a slice of pageantry that offers more up-close, blade-and-braid razzle-dazzle than a lifetime's polite parades on Tarmac. I am now keenly aware that the King's Troop are based in Woolwich, but fire their salutes from Hyde Park or Green Park, involving the transfer of 80-odd horses and daunting logistics. Their rivals, the Honourable Artillery Company, blast rounds from the Tower of London. The latter may claim a more spectacular backdrop, but the former have thundering hooves, jangling harnesses and uniforms that date from Waterloo. As a proud officer rightly remarked, "No one looks bad in boots and breeches." Quite so - just ask Mr Darcy. Added to which, the KTRHA enjoys a particularly chummy relationship with the Royal family. When the last horse-drawn artillery was replaced by brutish machines in 1947, King George VI declared that a troop must be retained for great state occasions: hence the King's Troop (a title retained by our Queen, in honour of her beloved father). When the six teams of six sleek horses, drawing guns used in the Great War, assembled on the parade ground, all onlookers were rapt. Jaw-dropping horsemanship and precision was in thrilling evidence in Green Park, which is where we privileged spectators processed after the troop had trotted out of the barrack gates to cheers from the waiting crowd. I particularly enjoyed the expression of composed hauteur on the female troopers" faces, as a visiting general took the salute: clearly nothing gives you a sense of martial pride like mastering 17 hands of gun horse. There was a blissful moment of internecine comedy when a troop of Household Cavalry (Blues) came trotting past the parade ground. "Typical," snorted a senior officer. Trying to steal our thunder. But there's precious little chance of overshadowing the polished, buffed, glittering King's Troop. I like to think of myself as some sort of minor connoisseur of national pageantry, having waved my flag at assorted royal weddings, jubilees and garter ceremonies. Yet there was something uniquely moving about standing in Green Park, waiting for the first faint clink of tack and hoof-fall. A military band ramped up the atmosphere with the theme tune from Black Beauty, the hairs stood up on the back of my neck, and in a heartbeat there they were: the six gun teams swept into view over the brow of the hill, charging through the trees at a tremendous, ground-shaking lick, like a vision straight from 1815. Officers on prancing chargers barked commands and saw the guns detached on to their marks, everyone working with split-time precision. And then, at the exact stroke of noon: boom! The first gun nearly shattered my ear-drums. Twenty rounds for Prince Philip, plus another 20 for the Royal Park. The air reeked of cordite, horse sweat and leather, and a fine mist of gun vapour trailed through the trees. National pride had been satisfied and people blinked back tears. This July, the King's Troop will trot out to greet a new royal baby, and wise Britons will head to Green Park.