The elusive artist Banksy has confirmed he painted swimming fish on to a City of London Police sentry box, which was first spotted on Sunday morning.

The glass-fronted box on Ludgate Hill - near The Old Bailey and St Paul's Cathedral - has been transformed to look like an aquarium.

This is his seventh new artwork to be revealed in the capital in as many days.

Since Monday, stencilled silhouette images of a goat, elephants, monkeys, a wolf, pelicans and a cat have popped up in various locations across London.

This work differs from the previous works by Banksy unveiled this week in that it is a detailed painting that appears to have been created with translucent spray paint.

Two City of London Police officers have visited the sentry box and taken pictures.

One officer said the art was picked up on CCTV cameras and they were asked to come and have a look.

He added that they were waiting to hear what will be done about it.

In a statement, Det Ch Insp Andy Spooner said: "We are aware of criminal damage to a City of London Police box in Ludgate Hill.

"We are liaising with the City of London Corporation who own the police box."

A local resident came to take pictures of the fish artwork as she heard it could be by Banksy said: "I walked up here yesterday and I don't remember seeing it, I think I would have noticed it.

"I like it, it's got a charm to it somehow. It's not in your face, it's quite subtle.

"I know some of the others have been stolen, so I wanted to come and see it.

"It's actually rather beautiful in the sun."

Three people travelled from the West Midlands to London for the weekend to see the latest Banksy artwork around the city.

Before it was confirmed as Banksy's a man, who had travelled from the Black Country said he was not sure if the fish art was by Banksy and he had seen reports of a seal elsewhere which they were going to go and see.

He said: "We've come down this weekend, we're big Banksy fans."

Another man in the group said if the fish artwork was Banksy's, it was probably his favourite of the ones revealed this week.

Along with CCTV and road-narrowing bollards, police sentry boxes like these were installed around the Square Mile in the 1990s to protect the City from terror attacks during the IRA troubles. Police officers stood guard in them to monitor traffic.

On Saturday, the artist's sixth piece - a stretching cat on an empty advertising billboard - was removed from its location in north-west London hours after it was revealed.

Crowds who had gathered to look at the work booed as the piece in Cricklewood was dismantled by three men who said they were hired by a "contracting company" to take down the billboard for safety reasons.

Banksy's translucent fish swimming around a 1990s police sentry box form the seventh piece in a surprise animal-themed art series.

On Monday, a goat appeared on the side of a building near Kew Bridge, followed by a sweet image of two elephants touching trunks on the side of a house in Chelsea on Tuesday.

Three monkeys hanging from a bridge in Brick Lane then drew crowds on Wednesday.

On Thursday, a howling wolf on a satellite dish - which looked like the wolf was howling at the moon - was installed onto a garage roof in Peckham.

On Friday, locals in Walthamstow woke up to find two pelicans fishing above a fish shop.

In total, three of his works unveiled this week have been removed or defaced.

The wolf on the satellite dish appeared to be stolen by masked men within hours of being revealed and the affectionate elephants were pictured having been painted over with stripes on Friday.

Each day, the artists officially announced the works on his Instagram page.

Additional reporting by PA Media.