London (CNN)A climate protester from the global environmental movement Extinction Rebellion has climbed scaffolding around the base of one of Britain's most famous landmarks, the Big Ben clock tower of the Houses of Parliament.
Extinction Rebellion activist climbs Big Ben scaffolding
Videos shared on social media showed the protester unfurling banners reading "No pride on a dead planet" and "Citizens' Assembly" once on top of the scaffolding.
The man was reportedly wearing a costume and a blond wig resembling Prime Minister Boris Johnson's distinctive hairstyle.
"Tree surgeon Ben Atkinson, 43, has begun a free solo climb of Big Ben and will drop an Extinction Rebellion banner to highlight Government inaction on the Climate and Ecological Emergency," the group said in a statement.
London's Metropolitan Police said: "Police were called at 15:33hrs on Friday, 18 October to reports of a man climbing up scaffolding surrounding Big Ben. Officers remain on scene."
The activist group has defied a London-wide public order ban issued on Monday by staging protests outside Downing Street and blocking the busy Oxford Circus intersection with a wooden pyramid.
The Metropolitan Police said the crackdown was intended to prevent "ongoing serious disruption to the community."
Extinction Rebellion decried the ban as an "erosion of democracy" and called for greater attention on the climate crisis.
On Thursday, London commuters dragged Extinction Rebellion protesters off the top of a subway train as clashes broke out between passengers and activists.