Outside the Old Sheriff Court in Ingram Street, where Chopin performed the year before he died, men from the council are cleaning the stone benches and blitzing chewing gum glued to the pavement.

It is all to do with the Commonwealth Games, explains the concierge as he ushers cigarette butts into the gutter, in anticipation of which Glasgow is undergoing the kind of makeover in which brides-to-be are apt to indulge.

We are in the heart of the Merchant City, that part of the fabled Second City of the Empire which turned the blood, sweat and toil of workers in the factories and the shipyards into hard cash and conspicuous consumption. Hereabouts everything is conceived on an Egyptian scale and it's easy to imagine it in its 19th century heyday, when it thrummed with ambition and pulsated in the pursuit of profit.

On the other side of the road is Hutcheson's Hall, with its clock tower and tuxedo-white facade. Set against a cloudless blue sky, it looks like something out of a fairy tale or Disneyland. It is named in honour of the Hutcheson brothers, George and Thomas, who made their fortune in the 17th century in banking and land. They left money to build "a hospital for entertainment of the poor, aged, decrepit men" and a school for orphans. Both of course are long gone, the latter having metamorphosed into the fee-paying school of the same name.

For now, however, the hall, which is owned by the National Trust for Scotland, has been invaded by an army of hard-hatted, steel toe-capped, bantering builders. When it reopens, says the concierge, it will be as a swanky restaurant, with which the Merchant City is not under-endowed. There are no pawnbrokers or pound shops in these precincts. Such shops as there are sell Armani suits and Bang & Olufsen stereos and Agent Provocateur underwear. There is a champagne bar on the corner of Hutcheson Street and further along Ingram Street, going toward the city centre, there is the Corinthian Club, a bar, restaurant and casino which never closes and which, press reports say, is facing an "uncertain future" because of outbreaks of alcohol-fuelled violence in the wee small hours.

When I started visiting Glasgow regularly, 25 years and more ago, it was to this part I came. The then Glasgow Herald was based in Albion Street and my memory is one of darkness, decay and drink which, coming from perjink Edinburgh, felt like going from a Sunday school picnic to a stag party. Once, I was taken to lunch at Rogano on Royal Exchange Square. "Two pints of lager and let's have a look at the wine list," my host barked as we passed the bar en route to the restaurant. Glasgow felt edgy, insistent, urgent, exciting, like one of de Niro's early movies. You never knew, as William McIlvanney wrote, where the next invasion of your privacy was coming from. What one swiftly learned, however, was never to underestimate or patronise anyone. In the Horseshoe bar, the ambience may have been reminiscent of a saloon in the Wild West but the Bard's "drouthy drinkers" were extraordinarily well-read and informed, and ever ready to share their knowledge.

That much has not changed about Glasgow. But the efflorescence of the Merchant City, while ridiculed by some as yuppification, is symptomatic of Glasgow's determination to pull itself out of the post-industrial mire. No other British city, claims Baillie Liz Cameron, has had to contend with the scale of deprivation that afflicted Glasgow in the years after the Second World War when one heavy industry after another was lost. Inevitably, it has taken longer than anyone expected for it to rejuvenate. You can't replace one industry overnight with another. It takes time and patience, commitment and capital.

"When people ask me when Glasgow will be finished," says Cameron, "I tell them it will never be finished. It's a work in progress." We are in the members' library in the City Chambers in George Square, the proposed development of which has of late caused a humdinger of a stushie. Built between 1882 and 1890, its lavishness takes the breath away. So profligate was the use of the marble in its interior, it's a wonder there's any left in Carrara's quarries.

Cameron has been a baillie for 11 years and a councillor for 22. From 2003 to 2007 she was Lord Provost. Currently, she serves as an Executive Member of Development and Regeneration Services, with a brief that is as broad as the mouth of the Clyde and which may be summed up by adapting the old slogan - to make Glasgow miles better. She is, she says, with a gleaming smile, a Glaswegian first and foremost, then Scottish, then British. Were independence for the city on offer in September, one suspects she would be at the forefront of a Yes campaign.

As it is, she says she will be "proudly" voting No. Could this be because she is a member of the Labour Party? "If I weren't a politician I'd still be voting No," she says, adding: "I don't like any taint of victimhood. We were part of the Empire as well. We [in Glasgow] have a lot in common with people in Birmingham and Sheffield and Manchester and Leeds. For me being part of the Union will always be important. It's not unpatriotic to vote No."

Having said all of which, she insists that, whatever happens in the autumn, friends who think otherwise will still be on her Christmas card list. Cameron is typical of Glaswegians who, while not in any way oblivious or insensitive to the city's carbuncles, have faith in its essential goodness and greatness. Her enthusiasm, conveyed with wit and passion, is contagious. Stepping out on to George Square the sun is still shining, the grass Celtic green, the sky Rangers blue. Parking myself on a bench to savour the moment, I am joined by two elderly, time-rich gents, Bill and Jimmy, who as it turns out are representatives of both sides of the Old Firm and also the referendum debate. Bill reckons independence is a good thing because "we'll be able to make our ain midden" while Jimmy is fearful that his pension may "just evaporate". Though fundamentally opposed to each other's views, you sense that they will be sharing the same bench this time next year.

This is part of Glasgow's irrepressible charm. Its citizens, unlike their counterparts at the other end of the M8, appear to thrive on a diet of what a colleague once described as "fish and chutzpah". If there's such a being as a diffident Glaswegian I have yet to meet him or her. Offer them an opportunity to stand out from the crowd and they seize it as they might a lost lottery ticket. Perhaps this accounts for the number of buskers you see in Buchanan Street, Sauchiehall Street and Argyle Street. And what buskers they are. Today, outside the Concert Hall, there's a young man with a drum kit, thrashing away like Ginger Baker in his pomp, creating the kind of din that seems designed to awaken the dead. In Edinburgh, where the noise even on a Saturday afternoon never rises above a murmur, you could imagine the reaction. Here, however, a crowd gathers and a few people begin to bop to the beat, egging the drummer on to give it laldie.

It is on the street that Glasgow's gallusness, its conceit of itself, is most apparent. In the past, there was always someone - usually a bloke called Jack - who seemed to epitomise this, none more so than Jack House, known to all and sundry as Mr Glasgow. Self-appointed, Jack made it his business to "stick up" for the city in an era when few had the will to do so. In particular, he loved its joie de vivre, its music-hall approach to life's travails. His praise was hyperbolic, his amour that of a blind romantic. "Walking down Renfield Street on a wet day," he once wrote, "is to me a more rewarding experience than promenading Fifth Avenue on a fine day, and I have done both."

I have come to feel similarly, though my street of choice is Ingram Street, which runs from Royal Exchange Square and the Gallery of Modern Art through the Merchant City to the High Street. As I walk the long mile I realise I am going back in time, to the origin of the Dear Green Place. What would Jack House make of it now? My guess is that he would be both appalled and fascinated, stunned by the disappearance of so many familiar landmarks and amazed by the area's metamorphosis.

Cathy McCormack's Glasgow is different again, and not in a good way. Now in her early 60s, she has lived in Easterhouse for 40 years. In 1974, it was a new estate, one of Billy Connolly's "deserts wi' windaes". In her memoir, The Wee Yellow Butterfly, she described her ground-floor council flat when she and her husband Tony moved in as being no better than a concrete bunker. "It had a gas fire in the living room and an electric fire on the wall of one bedroom, but no heating in the other rooms or in the hall. There was nothing to keep the heat in or the cold out. Neither was there any ventilation."

Have things changed for the better in the intervening period? "Well, people have got front and back doors now," says McCormack, "but the reality hasn't changed. Unemployment. Poverty. The unemployed and working classes have been totally demonised. And they're being punished. People are being left without food. That really angers me so much."

McCormack cut her teeth in community activism, and was one of the founder members of Easthall Residents Association, which does what it can to help people who find themselves on the edge. She experienced at first-hand how deprivation and ill-health was passed from one generation to the next. "My field, poverty," she's said, "has become an industry." In the 1990s, she addressed the United Nations, the World Health Organisation and the Westminster government. Touring Nicaragua and Soweto she was struck by similarities with Glasgow.

Her message, then as now, is that people can make a difference if they have a will and they're prepared to organise themselves. Party politics is not for her, she says; she prefers grassroots campaigning. Her hope for the the future can be summed up in one word: independence. "George Galloway says that if Scotland votes Yes then England will be condemned to a Tory party for ever. But that's the case anyway. People in Scotland have not had the party they voted for in decades. At least with independence there's a possibility that things will get better. I don't think we've got a choice."

As I walk from the city centre through the east end vaguely in the direction of Parkhead, her words take on fresh potency. Beyond Trongate the buildings look frail and gimcrack. In the space of a few hundred yards, you move from an area where you might live until you are nearly 80 to one in which you'll be lucky to see 60.

A cafe offers, "Any single hot roll with tea or instant coffee £1.80 (ends 11am)". In the Gallowgate is Glasgow's "oldest chippie", established 1884, though it looks as if its frying days are over. A few Irish tricolours flutter in the breeze. There's an abundance of litter and graffiti and a sense of emptiness and lack of ownership. It is a scene even Jack House would have found hard to romanticise. Like many Glaswegians, he preferred myth to reality, illusion and delusion to fact, veneer to substance. His Glasgow was steeped in richly varnished stories and peopled by "keelies". It was hereabouts, he liked to remind his readers, that Barr's used to manufacture Iron Brew which overnight was renamed Irn-Bru. Jack dubbed it "the wee boy's Drambuie" because, like the liqueur, no-one except its makers knows what exactly goes into it.

There are just a couple of months to go before the opening ceremony for the Commonwealth Games, which will be held at Celtic Park. In anticipation, there are dozens of workmen building walls, laying paving, planting trees. One of them volunteers that one of his previous jobs was at the Olympic Village in London. From his accent I guess he is Welsh. His reply, laced with four-lettered words, suggests that my linguistic antennae may not be what they once were. Opposite the stadium is the Commonwealth Arena and the Sir Chris Hoy Velodrome, known for sponsorship reasons as the Emirates Arena, which will host the badminton and cycling events. Nearby, encased in lilac-tinted hoardings, is a wasteland, which we are led to believe offers "A Golden Opportunity!" to anyone interested in transforming it into retail and leisure units. Leisure, one can't help but think, is not a high priority in these parts. Eager to canvass local opinion, I spy a solitary woman returning from a shopping expedition. If she has a view of the referendum she doesn't offer it. As for the athletes' village, which will house 6500 athletes and officials during the Games, after which it will be occupied by local people, she is not impressed. "Nae buses, nae shops," she intones, as if it's her catchphrase.

Her scepticism is understandable in historical context. As Cathy McCormack once said: "We experienced social and economic apartheid for years, and we cannot go on like this." Artist Kenny Hunter would agree. He has given Glasgow two of its most emblematic, contemporary sculptures, the millennium figure of Jesus Walks Among Us, and Citizen Firefighter, which stands outside Central Station. Bearded and be-dungareed, Hunter has a studio in Anniesland. Though he is a graduate of Glasgow School of Art, he is from Musselburgh and thus speaks with the caution of an incomer. Wary of generalisations, he recalls (on informing a friend he was moving west) being told, "Don't let the bastards cheer you up. They're all too bloody cheery over there."

In the past, he says, it would have been necessary for someone in his line of work to go to London. Not so today. Now you can be an artist anywhere. "It's about how you connect." He looks surprised when I ask how he'll vote in September; he is a Yes man. "Perhaps it's the circles I move in," he says, "but I know of only one artist who supports Better Together. He has a fear of Scotland becoming parochial, small-minded." Hunter's reputation is international and he is especially well-known in Europe. "I would love to send every Scot over to Denmark and put their minds at rest. The Danes have a great way of looking ahead."

A path leads round the athletes' village and takes you to the slow-flowing Clyde. Trees are budding and magpies hop from branch to branch, preening like playground bullies. It takes an hour to walk back to the city centre, during the course of which the river broadens and acquires the aura of a port. Glasgow and the Clyde are synonymous, the former dependant in the best of times on the latter for its prosperity. It was while launching a ship on the Clyde, Jack House recalled, that a Russian grand duke called Glasgow "the centre of intelligence in Europe". Moreover, it was the Clyde's yards which in the Second World War built and repaired more vessels than all of the USA's shipyards put together. One's heart swells at the memory, as one's head says that the time may have come to move on. n