The singing has long since stopped. In the first days of the Italian lockdown, Venice’s abandoned streets were full of music. Masked shoppers paused beneath open windows to catch a snatch of Mozart or Queen or Adriano Celentano. In the evenings, residents sang from their balconies across the calle, sharing a moment of hope and support. Rainbow banners were unfurled across the house fronts: “Everything is going to be all right” painted in colourful, childish letters. Most have now been folded away. The city is sullen, mistrustful. People no longer greet one another, passing by with lowered eyes. The only sound is the engines of the carabinieri boats, constantly patrolling the still canals.

Venice has always been a prison, its inhabitants incarcerated by the waters of the lagoon. There has never been much privacy here. Footsteps and conversations bounce between the tight walls of the alleyways and the narrow canals in a curious ventriloquism which turns the whole city into an echo chamber. Now the water traffic and the tourists are gone from the Zattere, you can overhear conversations from as far away as the Giudecca or San Marco.

When Napoleon conquered the city in 1797, he ordered a survey into its habits and opinions, but the attempt was fruitless. In the capital of masquerade, no one could be found who was willing to talk. Surveillance and secretiveness are deeply ingrained in the Venetian character.

My neighbour spends her days patrolling between balconies, photographing anyone who passes by. Last week she began to shout insults at me if I left the house to shop for food or to exercise alone within the permitted 200-metre limit. Then I had a call from my landlord. The woman had phoned his cousin (that’s how things still work here) to report that I had been seen sitting outside my front door reading a newspaper. I tried to explain that I had committed no infraction, but the sense of being spied upon was horrible.

Venice has always been a prison, its inhabitants incarcerated by the waters of the lagoon

The next day she reported me to the police twice, once for continuing to sit outside and again, in the evening, for carrying a cup of tea to the end of the alleyway to watch the sunset over the Redentore, Palladio’s magnificent plague church. The carabinieri weren’t very interested, but other neighbours complained at the disturbance. Whilst I had broken no rule, this woman’s hysterical vindictiveness means I no longer feel able to enjoy the small freedoms presently permitted by law.

Whispers rustle across the city. One friend was denounced for taking a box of vegetables to a neighbour’s doorstep, another for going outside onto her own terrace to smoke a cigarette. The next time I passed beneath the woman’s balcony, she screamed that I should “go back to where I came from”. I’m ashamed to say I lost my temper. In a scene from a Goldoni comedy shutters and windows banged open across the courtyard as the neighbours joined in the row. It should be funny, but it feels sickening.

The word “totalitarian” originated here in Italy, first as a term of derision used by critics of Mussolini, then adopted with pride by the Fascists in 1925. “We are not a ministry, we are not even a government. We are a regime,” Il Duce explained to the Chamber of Deputies in a speech the same year. In 1926, a decree on public safety exhorted the strictest of surveillance on even minor expressions of dissent, and during the next 17 years, government agents compiled more than 130,000 dossiers on Italian citizens, aided by a vast number of voluntary informers. Eighty per cent of denunciations were anonymous.

Venice has a much longer tradition of insidiously undermining social bonds and personal loyalties. On my way to the market, I pass one of the bocca di leone, the “lions’ mouths”, set into the wall near the Gesuati church. Since the creation of the Council of Ten — known as the “black inquisitors” after their masks — in 1310, the “mouths” were a repository for denunciations from all over the islands.

Give a frustrated curtain-twitcher a little glimpse of power and we quickly become afraid

An eighteenth-century document by a “Chinese spy” in the Marciana archive notes that “silence is the emblem of this government, everything is secret”. Venice’s administration became famous and internationally feared for its use of the sbirri, or secret police, whose techniques were imitated by the Stasi and the KGB. Despotism is so much easier when it becomes self-imposed. What is so unpleasant here is not the quarantine measures themselves, which are an entirely rational attempt to contain the pandemic which has caused such appalling suffering across the country, but what they have exposed about people’s readiness to convert their personal fear or malice into attacking their own communities at a time when bonds between neighbours are more vital than ever.

Give a frustrated curtain-twitcher a little glimpse of power and we quickly become afraid. It’s easier to comply with their self-declared authority; no one wants any fuss or trouble. Is that how it begins, I wonder? Suspicion where there should be solidarity, a creeping sense that no one can be trusted. Public spaces in Venice have become ominous. Leaving your home, even for legitimate reasons, makes you feel watched, oppressed, guilty — better to stay inside, better not expose yourself. The paranoia slides under the door like mist from the lagoon and the longer it continues the more tense and febrile the atmosphere becomes.

If there is a compensation for this anxiety, it is the loveliness of the city itself. Freed from the hordes of visitors, the cruise ships and crowds, it can be seen as it might have looked centuries ago, Canaletto’s lost light restored. The sheen of the water refracts dazzlingly against white Istrian stone, the lagoon gleams like polished jade. Find a corner on a quay away from prying eyes and you can lose yourself in the slow lap of the canals’ hypnotic radiance. It’s easy to forget that this is also a place of hidden gardens, of wisteria-knotted pomegranate trees and deliquescing jasmine. Perhaps Venice has never looked so enchanting, but despite the fragrance of its flowers and the eerie beauty of its emptiness, it has never felt so ugly.