A protester holding a Palestinian flag gestures from the side of the Elizabeth Tower, commonly known by the name of the clock's bell "Big Ben", at the Palace of Westminster, home to the Houses of Parliament, in central London. AFP
Pictures from the scene showed a cherry picker transporting him to waiting emergency crews on the ground.
London's Metropolitan Police force, which was first alerted to the climber around 0700 GMT Saturday, said the man was arrested after the "protracted incident".
The man spent the day perched barefoot on a ledge several metres up the landmark, even as emergency crews urged him to come down from the Elizabeth Tower in central London, more commonly known for its clock bell, Big Ben.
He was demanding the release of the Filton 18 political prisoners from Palestine Action, who were arrested for protesting against Israeli genocide in Gaza.
Negotiators had boarded a fire truck lift and used a megaphone to speak with the man, but footage on social media showed the figure in a hoodie and baseball cap saying: "I will come down on my own terms."
In the footage, negotiators indicated concerns about an injury to his foot, saying there was "quite a lot of blood" and that his clothes were not warm enough as temperatures dropped after nightfall.
AFP journalists at the scene earlier said the man appeared to be bleeding from his foot.
Crowds gathered from behind a police cordon, with supporters chanting "Free Palestine" and "you are a hero".
Police had closed off the surrounding area, including Westminster Bridge, while the Houses of Parliament cancelled tours.
Westminster police later said all roads in the area had been reopened.
On Friday night, pro-Palestinian protesters sprayed "GAZA IS NOT 4 SALE" in huge white letters on the lawn of US President Donald Trump's golf resort in Scotland.
The Palestine Action group said it was a "direct response to the US administration's stated intent to ethnically cleanse Gaza".
Police Scotland told AFP it was investigating after receiving a report of damage.
* This story was edited by Ahram Online.
Short link: