A graffiti artwork titled "Eton Posse", showing ex-public schoolboys David Cameron and Boris Johnson as rioters has appeared on a wall previously inhabited by a Banksy piece.

The picture, stencilled on a wall in Bristol, shows the prime minister and London mayor throwing bottles, echoing scenes from last summer's riots. The "Eton Posse" label is a reference to the public school both men attended.

The two have also previously faced criticism for both being members of the infamous Bullingdon club at Oxford and now it appears their Etonian past is also being mocked.

The graffiti, in Banky's home town, also features the word "Hoax" - which is believed to be a possible signature.

The graffiti in Bristol, which appears to show Cameron in white trainers and a hoody.

The artwork is not thought to be a Banksy original, as they are usually claimed by the artist on his website but has appeared on the same wall in Upper Maudlin Street where a Banksy mural was sprayed over last year.

The original artwork, opposite Bristol Children's Hospital, showed a crouched armed police officer with a child about to burst a paper bag behind him.

The incident in October last year was described by residents as an "act of vandalism" after it was covered in black paint.

In July, Banksy's gorilla in a pink mask painting on the wall of the ex-North Bristol Social Club, in Eastville, Bristol, was also painted over.

The building's new owner, Saeed Ahmed, said he had never heard of Banksy and mistakenly had the wall whitewashed.

Since Banksy made his name with his stencil-style guerrilla art in public spaces, his works have sold for hundreds of thousands of pounds.