The Colosseum, symbol of the Eternal City and one of the world’s most famous monuments, is at risk from vandalism and graffiti, Rome’s city authorities said yesterday.

Visitors to the 1st-century amphitheatre are taking away “chunks of stone” as souvenirs despite the presence of guards and surveillance cameras, according to Angelo Bottini, the Superintendent of Archaeology for Rome.

He said that most of the five million tourists who visited the Colosseum annually behaved responsibly. But others covered it in graffiti, left their rubbish behind and picked up bits of Ancient Roman wall or paving.

“Nothing surprises me any more,” said Professor Bottini. He said he had started an inquiry and was asking police to reinforce patrols and closed-circuit television surveillance at the Colosseum and the adjoining Roman Forum, where tourists also pocketed souvenirs.

At night, the sites are taken over by tramps sleeping rough in improvised shelters.

Professor Bottini said that funds allotted by central government for the restoration of the Colosseum had dried up two years ago and had not yet been renewed. He said that the authorities were drawing up plans to improve security measures at the entrance to the site.

They were also considering a clamp-down on unlicensed “fake centurions” who charge tourists for posing with them for photographs with the Colosseum as a backdrop.

The Colosseum, properly called the Flavian Amphitheatre, was begun in AD70 under Emperor Vespasian, the founder of the Flavian dynasty, and completed ten years later under Emperor Titus, Vespasian’s son. It seated 50,000 spectators and was used for gladiatorial contests and public spectacles such as wild animal hunts and naumachiae mock sea battles.

Once faced in marble, it was built over a drained lake in front of the Golden Palace of the widely detested Emperor Nero. It derives its name from the colossal statue of Nero, which stood near by, of which only the pedestal remains. The Colosseum was damaged by an earthquake in the 14th century and much of its stone was used to build mediaeval palaces and churches.

In the 18th century Pope Benedict XIV declared the Colosseum a sacred site because early Christians had been martyred there, and popes still lead Good Friday processions round the Stations of the Cross inside the amphitheatre. The crumbling and overgrown façade was repaired in the 19th and 20th centuries, with a big restoration project carried out in time for the 2000 millennium celebrations.

Last year, after the collapse of a wall on the Palatine Hill above the Forum and the Circus Maximus, Professor Bottini cautioned that many of Rome’s ancient monuments were crumbling. “We have a sick patient with many diseases,” he said.