WikiLeaks founder Julian Assange on Wednesday took his fight against extradition to Sweden to England’s highest court.
England's Supreme Court will hear the 40-year-old Australian’s appeal over two days, but are unlikely to render their decision for several weeks.
Assange was detained in Britain in December 2010 on a European arrest warrant issued by a Swedish prosecutor after two female former WikiLeaks volunteers accused him of sexual assault.
His lawyers argue that the warrant is invalid because it was issued by a prosecutor rather than a neutral judge or court.
Assange, who has been living on bail under virtual house arrest for 13-months while awaiting the outcome of his case, insists his sexual encounters with the two women were consensual.
If the seven justice panel from the Supreme Court rejects his appeal, the computer hacker turned whistle-blower intermediary could still make a desperate appeal to the European Court of Human Rights.
Assange infuriated officials in Washington by leaking thousands of classified US documents about the Iraq and Afghanistan wars.
He insists the charges against him and extradition proceedings are politically motivated, saying he fears he will eventually be handed over to the United States.
But officials in Washington are dubious over whether Assange is worth pursuing, with some saying a high-profile prosecution would be legally problematic and give him a popularity boost when he appears to be headed into obscurity.
Bradley Manning, the US army intelligence analyst accused of passing thousands of classified documents to WikiLeaks, is facing a court-martial on 22 charges including aiding the enemy and wrongfully causing intelligence to be published online.