0124 GMT February 18, 2020
Within hours of police hauling him out of the embassy, the 47-year-old Australia appeared in court for breaching his British bail conditions back in 2012 and to face a subsequent US extradition request.
After Assange was arrested and dragged into a police van in the British capital, American officials unsealed an indictment against him for computer hacking as part of his WikiLeaks whistleblowing activities.
The Sun tabloid reported he was being held in Wandsworth prison in south London, where he spent nine days in 2010 following an investigation over alleged sexual assault in Sweden that has since been dropped.
Deemed "the most overcrowded prison" in England at its last inspection in 2018, the 19th-century facility holds around 1,600 inmates.
Inspectors found "most prisoners share a cell designed for one person" while more than a third "were receiving psychosocial help for substance misuse problems".
Assange was remanded into prison custody Thursday at a short hearing in front of a London judge, who pronounced him guilty of disobeying his bail terms by fleeing to the embassy in June 2012. He could receive up to a year in prison when sentenced at an as yet undetermined later date.
His separate extradition case is set to be next heard by video-link at Westminster Magistrates Court on May 2.
Assange's London lawyer Jennifer Robinson confirmed he would be "contesting and fighting" his long-feared extradition to the United States.
WikiLeaks editor Kristinn Hrafnsson warned he fears the US will add more charges, meaning he could face decades in an American prison.
Assange sought asylum at Ecuador's premises in London's chic Knightsbridge district after a British judge ruled he should be extradited to Sweden to face the sexual assault allegations.
However, relations with his Ecuadoran hosts gradually soured and pro-US President Lenin Moreno on Thursday pulled his asylum, cancelled his citizenship and permitted British police to remove Assange.
Prime Minister Theresa May welcomed the arrest as showing "no one is above the law".
But opposition Labour leader Jeremy Corbyn, a leftist stalwart, called for the government to block the extradition.
"The extradition of Julian Assange to the US for exposing evidence of atrocities in Iraq and Afghanistan should be opposed," he said on Twitter.