As a string of new Banksy artworks spring up around London, an expert reveals the clues that unlock his art historical genius. Is Banksy a great artist? When a series of stencilled animals, suspended in silhouette, suddenly began to appear across London in early August, one a day for a week and a half, a chorus of headlines the world over asked: what do they mean? Warning: This article contains language that some may find offensive. Was the surprise rash of paintings from Kew Bridge to Peckham – a spree that featured a goat, two elephants, three monkeys, a wolf, two pelicans, a cat, a tank of piranhas, a rhino, and a gorilla helping a gang of beasts break out of London Zoo – nothing more than a static stampede of frivolous fun let loose in the dog days of summer? Or does the sequence contain hints of a deeper message and, just possibly, a clue to what Banksy has been up to all these years? Having studied every inch of the street artist's back catalogue for my new book, How Banksy Saved Art History, which explores how his work rewrites the story of art from prehistoric cave paintings to Pop Art, I was intrigued to see where this fresh trail of spray paint might lead us.

What I found is that, as ever with Banksy, there is more than meets the eye. Take the City of London police box, the target on Sunday 11 August of the seventh instalment in this series. Banksy's intervention into the urban object wasn't nearly as playful as it seemed.

Far from simply showcasing a "school of.