Man scales London's Big Ben with Palestinian flag, arrested after hours-long standoff (WATCH)

A man scaled London's Big Ben, waving a Palestinian flag, before being arrested after midnight following a protracted incident and negotiations with police.

London, United Kingdom: A man who scaled London's Big Ben, and spent the day perched on the historic clock tower with a Palestinian flag, was arrested shortly after he came down after midnight Sunday, police said.

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.

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.

"Every day in Parliament I see dozens of armed police officers patrolling Portcullis House and the parliamentary estate. Where were they today?" Conservative MP Ben Obese-Jecty posted on X.

"On Monday there needs to be a full explanation to MPs and staff as to how this protester was able to evade security so easily."

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.