A protective barrier will be installed around the Colosseum as a precaution measure to prevent passersby from dislodged fragments falling off the amphitheatre’s exterior walls.

The announcement was made on 27 November by Rome's superintendent of archaeological heritage, Maria Rosaria Barbera, who said her office had "a duty to intervene" for safety reasons.

The impassable security barrier will be composed of cast iron and cement pillars and will be erected at street level at “mathematically calculated” distances between six and 15 metres from the Colosseum.

The fascia di sicurezza concept was first presented to the public in early September when authorities ruled out the installation of “unsightly barriers” and even said that the use of an illuminated boundary was under consideration.

The move comes after a year that saw numerous incidents of mortar and fragments falling from the monument, although culture officials tended to play down the significance of these events.

Following media reports in July that the Colosseum was some 40 cm lower on the south side than on the north, authorities said there was no threat to the monument's stability.

The Colosseum is due to undergo a €25 million restoration scheme – including the cleaning and restoration of the entire building – in what will be its first comprehensive restoration in 73 years. Financing the project is shoe manufacturer Tod’s which in return for its funding will be granted the use of the Colosseum for marketing purposes for the next 15 years.

Ancient monuments across Rome have suffered structural damage over the last year, which experts blame on extreme weather conditions.