Never let it be said that when the festival begins the people of Brighton and Hove don't rise to the occasion.

This phallic artwork appeared suddenly on Saturday night after some cheeky artists decided to give the corner column of a private girls' school a paint job.

Passers-by were stunned to see the installation outside Brighton and Hove High School's senior department on the corner of Temple Gardens and Montpelier Road, Brighton.

Ben Griffith, 29, who lives nearby, said: "I was quite shocked. It was amusing to start with. At the same time it is disturbing because it is a girls' school. Everyone who was walking past was laughing. It is obviously amusing a few people."

Next to the column someone has daubed the word "Asbo" in purple paint.

Toby Bishop, 26, of Nizells Avenue, Hove, who works for Freshfields law firm in London, said: "I saw it on my way to work. It is pretty funny."

The makeover is thought to be a homage to the start of the Brighton Festival, during which bizarre artwork often seems to appear in unlikely public locations. But the police are not seeing the funny side.

Inspector Tim Piloni of Sussex Police said graffiti painters risked fines from £80 to thousands of pounds.

He said officers might be sent to the scene to carry out a forensic analysis. He told The Argus: "If someone reports something is in progress, we would respond to that very promptly.

"If something happened overnight, inquiries are carried out and it would be recorded as a crime. Penalties depend on the cost of the damage."