Street artist and political activist Banksy could finally be unmasked after police launched an investigation into potential "criminal damage" following an incident at the Royal Courts of Justice.

New artwork, depicting a judge beating a protester with a gavel, was spray-painted on the Grade I-listed building on Monday.

Despite being promptly covered up by officials, Banksy shared an image of the artwork with his social media followers.

Security guards have since been seen patrolling the scene as the artwork was concealed.

It was later confirmed that Banksy had been behind the artwork.

The Metropolitan Police said it had launched a probe into the graffiti following a report of "criminal damage".

Scotland Yard also confirmed that enquiries were continuing into the incident.

However, speculation that the police could uncover Banksy comes after the popular street artist has remained anonymous for nearly three decades.

If he were to appear in court, his name would have to be disclosed.

A wider picture of the artwork Banksy shared with his millions of Instagram followers

Banksy shared a picture of the artwork on his Instagram which has 13.4 million followers.

It was simply captioned: "Royal Courts of Justice. London".

The post showed the artwork, which depicts a demonstrator on the ground carrying a blood-spattered placard as a judge stood over them.

The piece was stencilled on an outside wall of the Queen's Building at the courts complex.

Banksy titled the Instagram post 'Royal Courts of Justice. London'

It was quickly hidden by large sheets of black plastic along with two metal barriers.

HM Courts and Tribunals (HMCTS) has said the artwork was going to be removed from the building.

"The Royal Courts of Justice is a listed building and the HMCTS are obliged to maintain its original character," a spokesman said.

While there is no direct explanation of the artwork, it appears to reference protesters being arrested.

It comes after nearly 900 people were arrested in central London at Saturday's demonstration in support of banned group Palestine Action - it is believed to be Britain's largest ever mass arrest.

Scotland Yard confirmed that around 1,500 people were in attendance, with 890 people being detained.

Campaign Group Defend Our Juries, which organised Saturday's rally, praised the work for "powerfully depicting the brutality unleashed by Yvette Cooper on protesters by proscribing Palestine Action".

The group added: "When the law is used as a tool to crush civil liberties, it does not extinguish dissent, it strengthens it."

A Metropolitan Police spokesman said officers had received a report of criminal damage "to the side of the Royal Courts of Justice".

Criminal damage holds a maximum sentence of up to 10 years in jail if more than £5,000 of damage is caused.

However, a sentence of three months or a £2,500 fine could be handed down if the damage is under £5,000.