Swedish authorities are coming to the High Court to try to block bail for WikiLeaks founder Julian Assange, pending extradition proceedings next year.
The 39-year-old whistleblower, wanted in Sweden for alleged sex offences, was granted bail at a court hearing earlier this week.
Bail conditions imposed at City of Westminster Magistrates' Court included the posting of a £200,000 cash deposit, with a further £40,000 guaranteed in two sureties of £20,000.
But in a dramatic turn of events, Assange was told he would remain behind bars while the Swedish Judicial Authority appealed against his release to a more senior judge.
Assange is expected to appear in the dock of Court 4 at the Royal Courts of Justice in London on Thursday for the appeal hearing, which is expected to last two hours, with every one of the courtroom's 200 seats occupied by the parties and the world's media.
The application is being heard by Mr Justice Ouseley who last week, in another high-profile case, rejected an appeal by South African authorities and allowed bail pending extradition proceedings for Shrien Dewani, the husband of a woman murdered on honeymoon in South Africa.
In the Assange case, an appeal was lodged after District Judge Howard Riddle told Assange he could be released from Wandsworth Prison in south-west London on condition he stay at the agreed address of a former British Army officer.
Vaughan Smith, founder of the journalists' Frontline Club, offered to house the Australian, who has made powerful enemies around the world as his website published 250,000 sensitive United States diplomatic cables.
Assange has received death threats and has spent the past week in solitary confinement.
Politicians in the United States have said Assange should be put on trial for treason and face the death penalty. Sarah Palin, the former Republican vice-presidential candidate, said Assange should be hunted down like the al Qaida leadership.
