Opinions on graffiti are as diverse as the designs themselves, which either blight or brighten city walls the world over, depending on how you view them.

The issue could not be more topical than in the Italian capital, Rome, where no less a person than the prime minister has immersed himself in the debate.

The ancient city centre, which is a Unesco World Heritage Site, is home to some of the most stunning monuments and architecture to be found anywhere in the world.

From the Trevi Fountain to the Coliseum, from the Pantheon to Bernini's Four Rivers creation in Piazza Navona, it has a rich fabric of history that many believe is gradually being unpicked by the sprayers.