AS you step off the train at Waverley Station and inch through the throng heading towards the Royal Mile, you get some idea of how the camel felt when faced with a needle. Two thoughts are uppermost for me at this time of year. How soon can I leave? And, where do all these people stay at night?

Since 1986, when I first was in Edinburgh for the Festival, I’ve never seen it this frantically busy. As headlines report complaints across the country about overpriced, insalubrious and surly hotels and B&Bs, in EH1 and environs such is the demand, a wheelie bin with a few mod cons could command a decent price. There are thousands of hotels and lodgings, but the explosion in visitor numbers is fuelled by Airbnb. This DIY business model is obviously adding to the hordes who can take rooms near the centre without worrying about a charmless reception or a miserly breakfast. Or, indeed, what the neighbours might be thinking.

This is not pure speculation. Figures from the property investment and management firm Grant Property indicate that in the past year, 75 per cent of buyers of flats and houses in the capital are from outwith Scotland, be it Ireland, Wales, England or far further afield. Recently, ahead of anticipated house price rises, there has been a rush to secure buy-to-let accommodation, mainly for students and holiday makers. In the past five years, the number of England-based landlords registered with one of the city’s main tenancy organisations has risen five-fold. As the London property market slowly cools, among the most popular streets for such investors, apparently, are Easter Road and Leith Walk – particularly attractive to purchasers from the Middle East it seems – where newly spruced-up tenements encourage the gentrification around Leith to continue apace.

It feels a very long time since I rented a flat at the foot of Easter Road, a street that grew darker and drearier the further it got from London Road. Even today walking along Great Junction Street, which connects Easter Road to Leith Walk, a shudder goes through me. It is part remembrance of the area’s poverty-stricken past – I once helped an old homeless man, who’d collapsed, out of the way of an oncoming bus in the dark, and later found my hands and clothes covered in blood. And it is part recognition that no amount of money can remove all evidence of its sometimes sinister history. As Irvine Welsh made clear in Trainspotting, in the early 1990s the further people ventured into these parts at night, the higher the risk of an unprovoked punch in the face.

Times change, and so does the character of a place. In countless ways, the development and upgrading of Edinburgh’s once proudly working-class quarters has been a boon, except, obviously, for those who could no longer afford to live there. To the growing middle-class who edged out previous inhabitants can now be added a stampede of arm’s-length landlords seeking to take advantage of the still affordable housing market, and in so doing squeezing out those who live and work in the area, but cannot match their bids.

The concern is not who is buying housing, but the use to which it is put. Owners from Timbuktu would find a warm welcome, if they were moving in. Sadly, too few spend even a single night as they decorate, fix and modernise before handing the keys to a letting agency. When the transient term-time cycle of students gives way, in the long summer break, to the rapid turnover of tourists, the city becomes like an egg that is hollowed out. Its outward appearance of a closely-knit and like-minded community is nothing more than a shell, and a fragile one at that.

The flight of city folk from the centre is happening the world over, but its effects are only slowly making themselves felt. Gradually, the personality and make-up of cities is becoming more elastic, temporary and disengaged. There was always an issue of neighbourliness, or lack of it, in urban centres. Compared with small towns and in the country, people could choose to remain strangers all their lives. But now, with so many people using flats as perches rather than nests, the way we live is altering. Not knowing the name of the person next door is no longer a choice but an inevitability. Meanwhile a floating population means no continuity or commitment or connection, no gradual strengthening of bonds and trust between households. An address occupied by students might be as quiet as a dentist’s waiting room – though unlikely – but the main problem is the fleetingness of their stay. That issue is multiplied to the nth degree by short tourist lets, their tenancy only as long as their suitcase is deep.

Conversations about preserving the architectural heritage of magnificent and vibrant world centres like Edinburgh involve experts and locals alike. But in the hidden and private world of flats – what you might call the dolls’ house economy – no authority holds sway but money. And that’s never good.