Poundbury is the King’s idealised town in Dorchester, built on his land to his specifications: the town that sprung out of his head. (‘My dream,’ says Harry Enfield in The Windsors, ‘was always to build a mixed-used residential suburb on the outskirts of Dorchester.’) It is so fascinating that I dream, briefly, of moving in for the completeness of the vision – who doesn’t want to live inside art? – and the portrait of the British class system in housing. Here it is, at last, laid out like a textbook: journey’s end.

It is becalmed on a Sunday evening, and sun saturated: there is almost no one about. Perhaps the residents are indoors, enjoying the lushness of their fittings. (The King is a noted perfectionist, and a very good watercolourist, better than Adolf Hitler.) Poundbury is a series of pastiche English cottages, townhouses and villas laid neatly alongside one another, like a practical demonstration of how to avoid a popular revolution over time with cohabitation. The late Queen Mother’s favourite hymn ran: ‘The rich man in his castle/ The poor man at his gate/ God made them, high and lowly/ And ordered their estate.’ This is the hymn in bricks. It looks like Islington built in another galaxy by aliens, to explain Islington to aliens who couldn’t make the journey, and they almost get it right. Still, it frays at the edges, like the Matrix. It is un-real: counties squashed into squares, and centuries into months. The effect is numbing.

The restaurant is called the Duchess of Cornwall Inn and it sits in Queen Mother Square, in front of a sculpture of the late Queen Mother. Her face is weirdly indistinct, like a thousand-year-old child. If republicans want to understand their failure, they should come to Poundbury. It’s a truism about the King’s towns – there is another near Newquay, called Nansledan – that for every social democrat who laughs at them, there are ten constitutional monarchists who want to live in them. They are finely made. There is a Little Waitrose and farmers’ cottages without farms.

The Duchess of Cornwall is as gaudy as Versailles. It is in a vast neo-classical house, many storeys high, filled with rugs, flowers and staircases: the result of a country-house fire sale, perhaps. There are baroque bookcases, Venetian windows, candelabras, and a picture gallery. The largest portrait is, quite tellingly, of Charles I. (This would-be absolute monarch was ill used. We get the point.) There are crumbs for subjects: the loos say ‘kings’ and ‘queens’ and are painted with crowns. It reminds me most of the Olde English restaurant in Trump Tower in New York City, which had Persian rugs and a defibrillator.

We order via app and pay in advance: we have no choice, there is a shortage of what tabloids call flunkeys. We order and we wait, wondering if the app has a panic button. Perhaps 45 minutes later it arrives: chicken Kiev and mashed potato; sirloin steak and chips. It is adequate pub food but the pub is not well run. The plates are uncollected, and I have to go in to ask for pudding, risking the glance of Charles I. When eventually a young woman brings the puddings (a banoffee pie, a triple chocolate brownie, which are good), she is undisturbed because she does not know the plates should be collected.

I don’t think I have been anywhere as odd as Poundbury, which does not mean I do not like it. Even so, a restaurant, like a monarchy, is dependent on the charisma of the staff. The Duchess of Cornwall has the jewels but not the manners, and I glory in the metaphor.