My heart goes out to republican-minded malcontents at this time. It must be dismal seeing the bunting go up in your street and have the papers gushing about how you should bake an Elizabeth sponge, if you regard the monarchy as a travesty that was outdated in feudal times. One friend has had to book a last-minute flight to New York to escape a public celebration he wants no part of.

The great thing about being the citizen of an actual republic, yet resident in a kingdom with functioning royalty, is that you can marvel at the pomp and ceremony, and absorb the sense of history, completely free of inner conflict. You can – as I, an Irishwoman, did on Tuesday – hail a taxi and say "take me to Buckingham Palace", without compromising your rejection of the hereditary principle. Some of my English colleagues were full of contempt. They would "have no interest whatsoever" in attending a garden party hosted by the Queen, they sniffed. Understandable, when austerity is being rammed down our collective tax-paying throats.

But wouldn't you have to be completely devoid of curiosity, or humour, to turn down an offer of tea at the home of any Head of State, let alone an extremely rich one about to mark 60 years on the throne? If nothing else, such an event provides an opportunity for some first-class social anthropology, or if you prefer, gawping.

With up to 5,000 people on the guest list, I was expecting long queues, airport-style security scanners, bag checks and perhaps fights breaking out over the scones. In reality, it was a highly dignified event that felt like a cross between a wedding (without the champagne or dancing) and the filming of a costume drama.

Security seemed to be in the hands of ageing toffs in top hats and tails who looked as if they'd ridden in from their landed estates. Yeomen of the Guard with shoes like the footwear of Morris dancers, positioned themselves should any of us lunge at the Queen. Not that anyone would have been that vulgar. People had dressed up and travelled from towns and villages all over the country. They seemed awed into whispers as they toured the rose garden, sat quietly listening to the military band, or edged forward like children, for a glimpse of any VIPs.

Not every fashion choice was the right one. But nobody at all had disobeyed the injunction about a hat being obligatory for women. Ceremonial chains rested on many a puffed-out chest while ecclesiastical robes in shocking purples and pinks mingled with all manner of armed forces garb.

The tea itself was worth the journey. We had miniature cucumber and mint sandwiches, Victoria sponge, scones and fruitcake (the doll-sized plates were obviously designed to put you off scoffing too much).

There was, of course, a firm reminder, if anyone in England still needs it, of class and hierarchy: the velvet rope separating you from somebody posher or higher up in the class pecking order. So we found ourselves herded outside the entrance to the Royal Tea Enclosure (Admission: Chosen Few, or perhaps foreign diplomats and Civil List hangers-on). That's when Kate Mountbatten Windsor swept past, thin as a reed and lovely in dusty pink. She told somebody later she found the garden party – her first – a "nerve-racking" experience.

Perhaps they hadn't told her about bread and circuses. All we had to do was enjoy tea and theatre. Cameras were banned (DVD available at £19.50) but by 6pm people were openly snapping pictures of each other with their iPhones on the lawn. And not even the Yeomen seemed to mind.

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