A new mural by anonymous street artist Banksy has appeared overnight on the walls of the Royal Courts of Justice in London, before being swiftly covered up by guards.
The mural is believed to be a response to the arrest of hundreds of demonstrators for supporting the banned group Palestine Action.
Banksy shared images of the work on Instagram on Monday, captioned: Royal Courts of Justice London.
By lunchtime, the artwork had been covered and fenced off by guards, who also placed CCTV cameras at the site.
The mural depicts a judge using a gavel to beat a protester, who is holding a blood-splattered placard while being knocked to the ground.
It was painted after almost 900 people were arrested at a London demonstration on Saturday opposing Palestine Action's ban. In recent weeks, hundreds of the group's supporters have been arrested while rallying at similar demonstrations.

Hours later, the mural was covered with two metal barriers, with security officials standing watch. Source: AP / Joanna Chan
Because the building is 143 years old, the mural will be removed with consideration for its historical significance, according to the HM Courts and Tribunals Service (HMCTS).
"The Royal Courts of Justice is a listed building and HMCTS are obliged to maintain its original character," HMCTS said in a statement.
The mural was Banksy's first artwork since May, when he drew an image of a lighthouse on a wall in Marseille, France, accompanied by the stencilled words: I want to be what you saw in me.
Supporters say latest artwork depicts 'brutality' of government ban
While Banksy never comments on his artwork, the London artwork has been interpreted as a statement on the arrests of demonstrators opposing Palestine Action's proscription as a terrorist group.
The UK government banned the group in July, after some members broke into a Royal Air Force base and damaged military planes.
Supporting or belonging to the organisation now carries penalties of up to 14 years in prison, placing it alongside groups such as al-Qaeda and the self-proclaimed Islamic State.
Defend Our Juries, which organised Saturday's protest, said Banksy's mural "powerfully depicts the brutality unleashed" by the government ban.
Police said hundreds of Palestine Action supporters have been detained in recent weeks under anti-terrorism legislation, including more than 500 in one day last month. Many of those arrested were over 60.
London's Metropolitan Police said people had been detained for a number of offences, including assaulting police officers and supporting a proscribed organisation.
Human rights groups have criticised the ban as disproportionate, arguing it limits freedom of expression and the right to peaceful protest.

Banksy has a long history of pro-Palestinian artwork, painting several large murals on the West Bank separation barrier in 2005, including the pictured Flying Balloon Girl. Source: Getty / Frédéric Soltan/Corbis
In August 2005, Banksy painted several large murals on the controversial Israel-built separation barrier, which runs around most of the occupied West Bank, including an image of two boys making sandcastles beneath a painted gap showing a tropical beach, and a girl lifted over the wall by balloons.
In 2007, a Banksy stencil of a rat with a slingshot — later dubbed Slingshot Rat — appeared on the wall before being cut out by unknown people and eventually resurfacing in a Tel Aviv gallery in 2022.
Banksy opened the Walled Off Hotel in Bethlehem in 2017, marketed as having the "worst view of any hotel in the world", overlooking the barrier. It closed in October 2023, citing "major developments in the region" after the Hamas-Israel war erupted on 7 October 2023.
— With additional reporting by the Reuters news agency.