A new street artwork believed to be by Banksy, depicting a judge striking a protester with a gavel, appeared on the exterior of the Royal Courts of Justice in central London on Monday and was quickly covered by local authorities.

The image was stencilled on an external wall of the Queen’s Building on the Strand and was hidden behind large sheets of black plastic and two metal barriers within hours. Security guards were reported to be patrolling in front of the screen that now conceals the work.

Photographs circulated on social media gave a brief view of the piece before it was obscured. One posting on X, the platform formerly known as Twitter, showed images of the stencil and said the work was "currently being covered by the Westminster Council." The Daily Mail reported it had approached Westminster County Council for comment.

The appearance of the mural follows large-scale arrests in central London over the weekend. Police detained 890 people at a demonstration in Parliament Square on Saturday that was reported to have about 1,500 attendees, authorities said. Scotland Yard criticised what it described as the "intolerable" abuse of officers during the rally. Of the people taken into custody, 857 were reported as being held on suspicion of showing support for an organisation proscribed earlier this year.

Street art attributed to Banksy has intermittently appeared in the UK and abroad for more than two decades and often engages with political and social themes. In May this year, analysts and internet researchers identified a mural in Marseille that included the words "I want you to be what you saw in me." In August of the previous year, a series of nine animal-themed murals was sprayed at different locations across London, culminating in an image showing a gorilla lifting shutters at London Zoo.

Banksy first gained public attention in the late 1990s with pieces such as The Mild Mild West in Bristol. In 2003 he covertly installed work in Tate Britain. In 2018 one of his most widely reported moments came when Girl With Balloon partially shredded itself after being auctioned at Sotheby’s; the altered piece was later retitled Love Is In The Bin and subsequently sold for £18.6 million in 2021.

The artist’s identity has been the subject of investigation and speculation for years. A 2008 inquiry by The Mail on Sunday named a Bristol man, Robin Gunningham, as Banksy, but the identity has not been conclusively confirmed.

Local officials moved to conceal the new work within hours of its appearance, and the area outside the Royal Courts of Justice returned to normal pedestrian traffic after the screen and barriers were put in place. Media outlets and social media posts provided the primary documentation of the stencil before it was obscured.