Elisabetta Pesce, the official with responsibility for the city’s security, said the latest policies are “aimed at improving the management of groups organised in the historic centre”.

The UN cultural body’s experts blamed the Italian authorities for a “lack of strategic vision” to solve the problems faced by one of Italy’s most picturesque cities.

Italian Culture Minister Gennaro Sangiuliano said Unesco had recognised attempts to address the island’s problems via an anti-flooding system and by the approval of the entry fee for tourists.

The picturesque fishing of Portofino, on the Italian Riviera, has brought in no-waiting zones in photogenic spots, with Instagram-happy tourists facing fines of up to €275 (£238) if they linger too long for that perfect selfie.

Away from Italy, Athens in Greece capped visitor numbers at the iconic Acropolis to 20,000 a day, to try to reduce damage to the ancient temple complex.

And in the Austrian Alps, the town of Hallstatt - said to have inspired the setting of Disney film Frozen - has built wooden barriers to block views in popular spots for a lakeside snap, on top of capping the number of tourist buses and cars entering the area.

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