28/04/2017 06:40 BST | Updated 28/04/2017 06:40 BST

Venice Is In Danger Of Becoming A Disneyland

In the weeks leading up to the Biennale, Venice hums with visitors. The city is used to it. From the Carnival in early February until the following November, every café table is adorned with a selfie stick, a map and a tourist clad in beige waterproofs. The Giudecca canal is periodically cast in shadow by the hulking loom of cruise ships, dwarfing even the tallest campanile. The citizens of Venice keep to themselves - darting down side-streets and back alleys, escaping the rush. If you follow them on their secret routes, you discover a second, quieter city, with laundry blowing softly in the wind, shuttered windows and a lone nonna bobbing home with her shopping.

La Serenissima is home to around 55,000 inhabitants, but that number shrinks every week. Come a particularly bad spate of acqua alta - high water - and residents will pack up and flee the city like rats, trading in the expensive, insalubrious Venetian palazzi for the safety and economy of the modern apartment buildings that line the streets of the mainland towns nearby. The vast majority of Venice's residential buildings are now shuttered against the sunshine, only visited occasionally by housekeepers and contractors who see to the endless to-do list of restoration and upkeep these places continually require. An institutional inertia hangs over the city as its buildings threaten to crumble. Waves from the looming cruise ships lap endlessly at their foundations, wearing them away.

On the vaporetti and in the little squares, mention the mayor to most Venetians and they will instantly lower their voice. But on my second night returning the floating city, I go to Campo Santa Margherita, the haunt of every young person on the island. There, I find a group of students drinking in the legendary Café Rosso, who defiantly want to be heard. In between downing shots of Fernet Branca, they tell me gleefully of their finest coup: they climbed the tower of San Marco at dawn and rolled a fifty foot banner down its length. Painted in red and black lettering were the words NO GRANDI NAVI - 'no big ships'. To make way for the enormous cruise vessels, huge channels are carved into the floor of the lagoon, accelerating erosion and upsetting the delicate ecosystem. "The water is supposed to flow gently in and out of the lagoon," one of them tells me in languid Italian, heavy with the soft, nasal accent of the Veneto. The channels mean the tides rush in, and the city floods and falls away. The students are part of a movement called 'Comitato No Grandi Navi', which have several headquarters across the city. The largest is Morion, a 'laboratorio occupato' - occupied space - in deepest Castello. It's a juddering, shabby club where you can buy a litre of vino sfuso - fresh, 'loose wine'- for €6, and dance to thumping rock music under NO GRANDI NAVI banners hanging from the ceiling.

At takes an hour to cross Venice by foot from end to end. About twenty minutes' walk from Morion is a silent, twisting back-alley that can only be reached after meeting half a dozen dead ends. There, you'll find the Da Mosto's palazzo, home to one of Venice's oldest families. More than a decade ago, Francesco Da Mosto starred in the hit BBC TV series Francesco's Venice. It was a love letter to the city, adored by UK and Venetian viewers alike. Francesco's wife, Jane, is British, and has in recent years become the voice of Venice's forgotten residents. She takes me off to a tourist café in the Rialto market, where loud, brash music bellows out and visored Japanese tourists crowd in little groups around rickety plastic tables.

Jane told me of how her organisation, We Are Here Venice, has been studying the impacts of cruise ships and exploring policy options for Venice. She also runs parallel projects, helping residents continue to forge their way in artisanal arts and crafts. "Cruise ships bring no benefit to the Venetians at all," Jane says. Tourists get off the boat, walk into San Marco, take a selfie, and then clamber back on board for lunch. Often they don't spend a cent - not even on a slice of pizza. "When it comes to the future of Venice, there are two groups of people. Those who think - and hope - it can stay on as a place for people to live and work, and those who believe it is destined to become a museum city, only fit to be visited." Across the water are the dormitory towns of Marghera and Mestre. "Go to Piazzale Roma first thing in the morning. The sight of 20,000 people streaming into the city on the commute is astonishing. They are coming to cater for the 30 million tourists that visit Venice every year." For Venetians, the situation has been at breaking point for some time.

With rents skyrocketing, Venice is in danger of becoming a Disneyland-style outpost of the 'real' cities on the mainland. On the Zattere, you can get a semifreddo at Nico's legendary ice cream bar and look out over the water towards the smoking chimneys of Marghera, where the Fincantieri shipyard turns out several cruise ships a year. It feels ominously like looking towards the future.