IMAGINE you have just bought a flat in Edinburgh’s New Town. Everything looks peachy. Then you hear the scrape of suitcases and stilettos, as braying students settle in upstairs for the new term. Soon the weekend parties begin. When you complain, their parents, who own the flat, call you a killjoy.

Meanwhile, from downstairs comes the drumbeat of Airbnb guests keeping alley-cat hours. The grocer on the corner has long since disappeared, and there is not a butcher or affordable bakery within an easy walk. Welcome to the land of metro shops and Harvey Nichol’s deli counter.

As the Festival approaches, the decibels increase, as do litter, marauding gulls, and the sense of being a stranger in your own city. In October, when you decide to sell, your estate agent recommends mentioning what profitable business neighbouring properties have been doing with short-term lets. The place is under offer in days, and you can start hunting for a cottage on Rannoch Moor.

It is only 250 years since the wealthy began to flee the Old Town for the quiet elegance of the New. Now, the equivalent of New York’s white flight is under way as residents in one of the loveliest capitals in the world pack up. Those who stay do so with gritted teeth. Meet one, and conversation quickly turns to the depredations on St Andrew Square, in the name of so-called art, or the habits of migratory tenants on their once well-maintained stairs.

Ahead of the final decision on turning Edinburgh’s Old Royal High School into a deluxe eye-sore hotel, signatories such as Carol Grigor in a letter to the council make the point that this choice will be “monumental”. It “goes far beyond the redevelopment of a single listed building... This is a red line we should not cross for the sake of narrow commercial interests, not when there is a better option.”

That option is a proposed international music school which Ms Grigor is helping fund. The contrast is stark: one venture continues to turn the city into a cash cow, in so doing undermining its heritage; the other builds on Edinburgh’s reputation as a centre of culture and learning. In other words, of enlightenment. What an old-fashioned concept that now seems.

Essentially, the Old Royal High is the canary in the mine. Already permission has been granted to countless unsympathetic new-builds, from a towering hotel in the Cowgate blocking light to Central Library, to the soulless development in Caltongate. Each was a blow to the amour propre of the capital, an assault on its architectural integrity. But if the Old Royal High is transformed into yet another hotel, this will be a tipping point, marking the moment when the city’s future is set, possibly irrevocably, in a direction that benefits no-one.

No, not even the hospitality industry which at the moment is revelling in unprecedented numbers of visitors. Because when the very things that make Edinburgh uniquely attractive are eroded, when the quality of life for residents is cynically depleted, sightseers will find themselves in streets richer in hotels and bars than in history or modern cultured life. Soon it will be an oyster without a pearl.

There is nothing wrong with wanting to encourage tourism. Quite the reverse. The problem, however, is that too many dire decisions have been justified in the name of culture, when those signing them off do not understand the meaning of the word. What message will it send when a former school is turned into a hotel where nobody who works or lives in EH7 could afford to spend the night? The council might as well run up a flag on its own horrid headquarters bearing pound and dollar signs.

Even the much-vaunted festivals are losing some of their lustre. How can a £22 ticket to enjoy Alex Salmond making dreadful jokes be called culture? The very notion of art and entertainment has been debased, but to say so brings accusations of elitism. Yet this is not to decry the wilder or crasser events, but to beg merely for regulation. In other words, for some overseeing authority to consider the whole picture, and make strategic plans that will enhance the city. Without that, it will be grated away, like a piece of choice pecorino, until only a mouldy rind is left.

Sadly, it is pointless even to write this. Edinburgh City Council rarely listens to what citizens say. A friend who has lived in the Grassmarket for more than 40 years complained to a councillor about recent planning decisions. He was told that if he didn’t like living in Edinburgh any more, he should leave.

When long-standing residents are made to feel unwanted, an obstacle to commerce, then all balance – and sanity – has been lost. The New Town’s construction was founded on principles of harmony and proportion. Unless something is done soon to save the capital, those virtues will soon be as historic as the Royal Mile.