Rival artist Robbo doesn't think the piece is a genuine Banksy.
A pub in north London is buzzing after discovering what they think is a 'Banksy' artwork painted on their garden wall - but others are not convinced.
Owners of the Princess of Wales pub in Primrose Hill caught a graffiti artist on CCTV painting a lion and a little girl on the wall - very similar to the work of renowned street artist Banksy.
The owner of the pub was all set to paint over it until customers suggested it could have been done by the celebrated stenciller.
But Banksy's arch rival Robbo is not convinced it's his work - and if it is he's losing his touch!
Robbo says: "It's not very good. It's a Banksy wannabe. It's got no real definition and if it is his, then corr, he's slipping!"
Is it real?
The during the noughties, the cult of Banksy grew from his work in his home town of Bristol to the streets of London where his famous rats and potent slogans started popping up all over. His work has even been found in New York and Israel.
In 2008 a mural sold for more than £200,000 on eBay and celebrities lined up to buy his work.
So how do you know if the mural at the end of your street is a genuine Banksy?
Robbos says he's known mysterious Banksy for years
What Sotheby's does when it has a painting attributed to Banksy is ring his dealer, Steve Lazarides, who owns a gallery in Soho.
But that's no good to someone who stumbles across a Banksy-like scene under a railway bridge or on the side of a house and wants to know if it's real.
Bill "Kilo" Pengelly, a legal graffiti artist who works on street-art projects with teenagers, is something of an expert. Two key signifiers of a genuine Banksy work are a busy location and a political subject, he says. While other graffiti artists go for railway lines or rundown areas to reach their community, Banksy aims for the wider public.
"He would do something in the middle of Oxford Street, but others get the areas where the walls either have permission or no-one bothers about them, in the middle of the worst housing estate or an abandoned warehouse."
Banksy's work is bigger, bolder and more elaborate than others, says Kilo, but technically not very advanced.
"If you look in a graffiti stencil book you will see work like this or better, but the difference with Banksy is where he's doing it and the topics."
Areas like Old Street and Vauxhall are full of Banksy imitations, but the works lack detail, partly because Banksy uses multi-layered stencils while others use just one.
In the past few years there has been an explosion in Banksy imitations, he says, some of which seek to fool the viewer by including the Banksy logo and recurring motifs such as a monkey.