Banksy could finally be unmasked as police launch an investigation into possible 'criminal damage' after a new artwork was sprayed on the Royal Courts of Justice in London.

The mural, which depicts a judge beating a protester with a gavel, was graffitied on the Grade I-listed building on Monday, before being swiftly covered up by officials.

Security guards were later seen patrolling in front of a screen concealing the work confirmed as being by the renowned street artist.

The Metropolitan Police said it has launched a probe into the graffiti after receiving a report of 'criminal damage' and that enquiries are continuing.

Banksy has remained anonymous for almost three decades but he would have to disclose his name if he were to appear in court.