Part of Westminster was brought to a halt for nearly three hours as a naked man straddled a statue in front of hordes of onlookers.
He was seen in a variety of poses on the statue of Prince George in Whitehall, central London, at times balancing precariously on the duke's head.
Onlookers said he was clothed before he climbed to the top of the statue.
The man was seen waving his arms around and was talking to crews on the ground as crowds of onlookers gathered.
The man was eventually coaxed down shortly before 3pm and put into the back of a police van. He was detained under the Mental Health Act, Scotland Yard said.