Key cultural figures have petitioned the Italian government for enormous cruise ships to be banned from the picturesque lagoon in Venice.

“We write to appeal for your active support … in safeguarding the city of Venice and its Lagoon,” the 21 signatories said in a letter published Thursday, addressed to Italy’s Prime Minister Mario Monti.

“Public opinion throughout the world regards the protection of Venice as a matter of extreme concern,” it said, stressing that decisions taken “often run contrary to the simplest criteria of prudent foresightedness and common sense.”

The petition, signed among others by Pierre Rosenberg — a former director of the Louvre museum — and American crime fiction author Donna Leon, warned the ships could cause serious damage to the environment and Venices heritage.

The letter slams “the increasing, invasive and uncontrolled presence of enormous cruise liners in the Lagoon, even in the immediate vicinity of the uniquely important buildings and sites around St. Marks Basilica.”

The signatories said they were “surprised and shocked” that a restriction imposed in March which banned ships of over 40,000 tons — only a little smaller than the Titanic — from entering St. Marks Basin had been suspended.

The ban on cruise ships sailing too close to the coast in Venice and in nature reserves was imposed after the shipwreck of the Costa Concordia luxury liner off Giglio island in January, notably to protect the environment.