Informal discussions have already been held between US and Swedish officials about the possibility of WikiLeaks founder Julian Assange being delivered into US custody, according to diplomatic sources.

Mr Assange was in a British jail last night awaiting extradition to Sweden, where he is wanted over allegations that he sexually assaulted two women.

The 39-year-old Australian was refused bail at City of Westminster Magistrates' Court yesterday on the grounds there was a risk he would abscond, despite a number of prominent public figures offering substantial sureties.

His arrest earlier in the day was described by the US Defence Secretary, Robert Gates, as “good news”. The US Justice Department is considering charging Mr Assange with espionage offences after his website released classified US diplomatic files.

Right-wing politicians in the US are pressing for his prosecution and even execution.

The Swedish government is seeking to extradite Mr Assange over alleged sex offences involving two women. Sources stressed that no extradition request from Washington would be considered unless the US laid charges against Mr Assange, and that attempts to send him to America would take place only after legal proceedings were concluded in Sweden.

Mr Assange went voluntarily to a London police station, accompanied by solicitors, after an international warrant was issued. The court heard that the film director Ken Loach, the journalist John Pilger and Jemima Khan, the sister of the Tory MP Zac Goldsmith, were among those offering to stand bail to the sum of £180,000. But District Judge Howard Riddle remanded Mr Assange in custody, saying there was a risk he might try to flee.

Loach, who offered to contribute £20,000, explained that he did not know Mr Assange other than by reputation, but said: “I think the work he has done has been a public service. I think we are entitled to know the dealings of those that govern us.”

John Pilger, who also offered £20,000, said he knew Mr Assange as a journalist and personal friend and had a “very high regard for him”.

“I am aware of the offences and I am also aware of quite a lot of the detail around the offences,” he told the court.

“I am here today because the charges against him in Sweden are absurd and were judged as absurd by the chief prosecutor there when she threw the whole thing out until a senior political figure intervened.”

Ms Khan offered a further £20,000 “or more if need be”, although she said she did not know Mr Assange.

Gemma Lindfield, appearing for the Swedish authorities, said she opposed bail because there was a risk Mr Assange would fail to surrender — and also for his own protection.

Ms Lindfield said Mr Assange was wanted over four alleged sex offences. One charge is that he had unprotected sex with a woman, identified only as Miss A, when she insisted he use a condom. Another is that he had unprotected sex with another woman while she was asleep.

Judge Riddle said: “This case is not, on the face of it, about Wikileaks. It is an allegation in another European country of serious sexual offences alleged to have occurred on three separate occasions and involving two separate victims. These are extremely serious allegations. From that, it seems to me that if these allegations are true, then no one could argue the defendant should be granted bail.”

However, he added: “If they are false, he suffers a great injustice if he is remanded in custody. At this stage in these proceedings, the nature and strength of the allegations is not known.”

Belfast Telegraph