There is a risk of "flagrant denial of justice" if Wikileaks founder Julian Assange is tried for rape in Sweden, his lawyer has told a UK court.
Geoffrey Robertson QC fears his client could be extradited to the US on separate charges relating to the publication of Wikileaks documents.
Mr Assange, 39, denies claims of sexual assault against two women.
His team said he was "willing and able" to co-operate with Swedish authorities, so no extradition warrant was needed.
At the extradition hearing, in London's Belmarsh Magistrates' Court, his lawyers also challenged the move on human rights grounds.
'Trial by media'Mr Robertson said there was a risk his client could be extradited to the US, or even Guantanamo Bay, and could face the death penalty as a result.
In a document released by the defence team, they argued that:
- Swedish prosecutor Marianne Nye is "not eligible" or an appropriate "judicial authority" to issue a European Arrest Warrant
- The Swedes are guilty of an "abuse of process" as they have not demonstrated any intention to charge or prosecute Mr Assange
- The application for a warrant is "disproportionate" as he is willing to co-operate and be interviewed by phone, e-mail or videolink
- The arrest warrant paperwork is not valid as it does not "unequivocally" state that he is wanted for prosecution
- The offences Mr Assange faces - unlawful coercion and sexual molestation - are not criminal acts under British law; and
- Extraditing Mr Assange to Sweden would be a "real risk of a flagrant denial of justice" and a "blatant breach" of British constitutional principles.
Mr Robertson also argued that the extensive press coverage surrounding events risked a "trial by media".
He said front-page articles had described his client as a coward for refusing to return to Sweden.
"There's a danger this kind of media campaign, media vilification, will prejudice this secret trial," he told the court.
He said Swedish rape trials were regularly held behind closed doors and unless the press were allowed in court, his client would not receive a fair trial.
He also attacked the conditions Mr Assange could be held in if extradited to Sweden, saying the remand prison in Gothenburg had been criticised for its treatment of foreign prisoners.
The whistle-blowing website has been used to publish leaked US diplomatic cables, as well as other sensitive material from governments and high-profile organisations.
Clare Montgomery QC, representing the Swedish authorities, told the court rape is one of 32 offences that warrants extradition.
She argued that the Australian must face charges of rape and sexual molestation under Swedish law, following accusations by two women.
Mr Assange's lawyers say the European Arrest Warrant under which he has been detained is invalid because he is only being asked to provide his account of events, but has not yet been charged.
Mr Assange arrived at court under an intense media spotlight, and supported by a number of high-profile campaigners including Bianca Jagger, Jemima Khan and veteran politician Tony Benn.
The Australian had his bail conditions amended so he could leave his adopted home in Norfolk to spend the night in Paddington, west London.
Several witnesses are expected to be called to court on Tuesday, and district judge Howard Riddle may yet reserve his judgement to a later date.
Mr Assange was released on bail by a High Court judge just before Christmas after spending nine days in Wandsworth prison.
He denies sexually assaulting two female supporters during a visit to Stockholm in August and claims the inquiry is politically motivated.
The extradition hearing is expected to last two days. BBC News
