A cardboard placard claimed to be by the street artist Banksy has sold for £10,000 at auction.

The piece – depicting a young girl clutching a bomb – is said to be one of dozens made for a protest against the Iraq War in 2003.

It had been kept in a flat by a protester until 2016, when it was sold to its current owner.

The placard had been estimated to fetch between £10,000 and £15,000 at the auction in Newmarket.

‘Iconic image’

Banksy created a number of different signs for the 2003 London protest but few originals have survived because they were either discarded in the street or confiscated by the Metropolitan Police.

Will Axon, senior auctioneer at Rowley’s said: “It is one of those rare occasions when you can genuinely call a picture iconic.”

Pest Control, which is responsible for authenticating works by Banksy, is quoted on the auction listing as saying it could not issue a certificate of authentication for work deemed as “street-art”.

Banksy, who keeps his true identity secret, began his career as a graffiti artist in Bristol but has since gained global notoriety for his unique, stencilled artwork on public walls and facades.