WikiLeaks founder Julian Assange has been returned to London's notorious Wandsworth prison despite winning bail from a British Court.



He will now be held there for another 48 hours while Swedish prosecutors, who want to extradite him to Sweden to face allegations of sex crimes, mount a High Court appeal against the decision.



Mr Assange's legal team, led by Australian born QC, Geoffrey Robertson, offered a total of £240,000 ($380,000) in surety, and agreed he wear GPS satellite tracking tags, report to police every day and adhere to strict curfews while the extradition case, set down for next month, goes ahead.



The magistrate, Howard Riddle, said he was satisfied that Mr Assange's release to Captain Henry Vaughan Smith, owner of London's Frontline Club, and his restriction to the 10-bedroom, 600-acre country estate in Suffolk would ensure he was not a flight risk.



Mr Assange, 39, looked impassive as Mr Riddle made his decision, but raised an eyebrow and smiled almost imperceptibly when Gemma Lindfield, acting for the Swedish authorities, flagged the possibility of an appeal.



This decision had to be made within two hours of the 3.20pm (British time) decision to grant bail - and now requires the appeal case to be heard in the British High Court within a 48-hour deadline.

Mr Assange's lawyer Mark Stephens said his client's relief at the bail decision had already evaporated, calling it "unfortunate" that "the Swedes won’t abide by the umpire’s decision".

Julian Assange arrives in a police vehicle for his court appearance. Credit:AFP

"They clearly will not spare any expense but to keep Mr Assange in jail," Mr Stephens told journalists outside the City of Westminster Magistrates Court in London. "This is really turning into a show trial."

Just 40 people were allowed into the courtroom. Supporters who entered the court included Bianca Jagger, human rights lawyer and friend Baroness Helena Kennedy and London caterer and restaurant designer Sarah Saunders, who told the court she had staked "everything" she was worth to help find the minimum £200,000 in bail required by the court.