Assange has been living at the embassy for about seven years when he sought refuge there.
The Metropolitan Police said its officers went into the embassy, to detain him for “failing to surrender to the court” over a warrant issued in 2012.
He has been taken into custody at a central London police station.
The Australian whistleblower has been holed up at the embassy, yards from the Harrods department store in Knightsbridge, since 2012, when he was granted asylum as part of a bid to avoid extradition to Sweden, where he was facing allegations of sexual assault.
The Swedish case has since been dropped, but Assange feared US extradition due to his work with WikiLeaks and remained in the embassy.
He has repeatedly denied any wrongdoing.
The Police said that Assange would be presented before Westminster Magistrates’ Court in London as soon as is possible.
Key Things Dates Linked With Julian Assange
1971: He is born July 3 in Townsville, Australia. During his nomadic childhood and youth, he attends 37 schools.
– 1990s: Becomes a computer programmer and software developer, with a talent for hacking.
– 2003-2006: Studies physics and mathematics at the University of Melbourne.
– 2006: Sets up wikileaks.org to enable whistleblowers to post sensitive documents on the internet without being traced.
– 2010: Swedish prosecutors issue an arrest warrant for Assange over allegations of rape and sexual assault involving two women. He denies the accusations.
– 2010: WikiLeaks publishes classified military documents on American diplomacy and the Afghanistan and Iraq wars, making Assange a pariah in the United States.
– 2012: To escape extradition from Britain, he requests political asylum from Ecuador and takes refuge at its embassy in London. Asylum is granted weeks later.
– 2016: WikiLeaks publishes 20,000 hacked emails from the US election campaign team of Democrat Hillary Clinton.
– 2017: Swedish prosecutors drop their rape probe. The same year, Assange becomes an Ecuadoran citizen.
– 2018: WikiLeaks’ attorney describes his living conditions in the embassy as “inhuman”.
– 2019 Ecuador’s President Lenin Moreno says Assange has violated the conditions of his asylum. British police arrest Assange, saying his asylum had been withdrawn.