Julian Assange is due back in court this morning to appeal against his extradition to Sweden to face accusations of rape and sexual assault.

The WikiLeaks founder will be at the high court from 10.30am for the latest stage of his battle to avoid being sent to Sweden.

Robert Booth is in court four of the Royal Courts of Justice and Paul Owen in the Guardian office; together we will cover the hearing throughout the day.

Assange will appear in front of two high court judges today: Lord Justice Thomas and Mr Justice Ouseley.

The accusations against him relate to a trip the 40-year-old Australian made to Stockholm in August last year. The Swedish authorities secured a European arrest warrant in December 2010, after which Assange was arrested and bailed.

His first appeal was in February this year. His defence team claimed that he would not get a fair trial and that his extradition was politically motivated. Assange's team said his arrest warrant amounted to an abuse of process because the allegations were originally dismissed and then reopened.

But City of Westminster magistrates court, sitting at Belmarsh magistrates court, found against him and ordered his extradition, leading to today's appeal.

Assange has hired a new legal team for the hearing today: Gareth Peirce, who represented the Guildford Four, the Birmingham Six and former Guantanamo Bay inmate Moazzam Begg, and Ben Emmerson QC, who specialises in European human rights law.

The WikiLeaks founder has been under house arrest for seven months in Ellingham Hall, Norfolk.

If he loses this week, he could appeal to the supreme court. The case is expected to last until tomorrow. But judgment is expected to be reserved, so a ruling might not be made public for days or weeks.

Robert Booth sends his first update from the royal courts of justice on the Strand in central London.

Assange arrived around 9.15am, giving no answer to questions as he moved at a snail's pace through a tight scrum of photographers. He was asked if he was looking forward to his latest day in court and whether he would take the case to the supreme court if he loses over the next couple of days. He said nothing and if anything looked mildly anxious though that may well have been the effect of the media scrum. He looked slim and smart in a navy suit and black shoes and was wearing dark-rimmed spectacles. He was carrying a heavily stuffed laptop bag. Around a dozen camera crews awaited him and more photographers. Also by the court railings are small groups of protesters. One is carrying the banner: "Free Assange! Free Manning! End the wars."

Bradley Manning is the US soldier arrested on suspicion of having passed classified material to WikiLeaks.

The accusations against Assange relate to alleged incidents with two women in Stockholm in August 2010. One accusation, that he had sex with a woman while she was asleep, amounts to rape under Swedish law. Assange denies any wrongdoing.

Assange has claimed that if he was extradited to Sweden in this case it would make it easier for the US authorities to seek to extradite him to face possible charges relating to his release last year of hundreds of thousands of classified documents, including US diplomatic cables and war logs from Afghanistan and Iraq. Assange's legal team argued before their last appeal that there was a "real risk" he could face the death penalty in the US or detention at the Guantanamo Bay prison camp.

The changes to his legal team – Gareth Peirce replaces media lawyer Mark Stephens and Ben Emmerson replaces Geoffrey Robertson QC – are thought to be part of a more conciliatory approach by Assange.

Peirce's office would not comment on their strategy yesterday, but she has previously been quoted indicating the need for sensitivity and respect in the case. She reportedly wrote to former US senator Tom Hayden for an article in US magazine the Nation:

Each of the human beings involved deserves respect and consideration. It is hoped that whatever steps as are required to be taken in the future will be taken thoughtfully, with sensitivity and with such respect.

Peter Tatchell, the human rights campaigner, has been having his say outside court. Tatchell said:

WikiLeaks and Julian Assange have provided a great public service in exposing US war crimes. The sex allegations must be taken seriously but he is innocent until proven guilty. So far he has not been charged with any offence. Swedish prosecutors and police need to interview him. There is no reason why they can't come to London. If he goes there I am sure the US will seek his extradition.

Here are a couple of pictures from outside the court – one of Assange from Robert Booth, and one of the banner mentioned earlier from Joseba Elola.

Campaigning leftwing journalist John Pilger is set behind Assange, Robert Booth reports. The press benches are packed in the grand, wood-panelled court.

Other supporters of Julian Assange in court this morning include WikiLeaks's Kristinn Hrafnsson, the Icelandic investigative journalist, Vaughan Smith, at whose house Assange has been staying under strict conditions since December, and Gavin MacFadyen of the Bureau for Investigative Journalism.

There have been hints online from a high-profile member of Anonymous, the loosely organised group of hackers sympathetic to WikiLeaks, that confidential US data might be leaked online to coincide with this hearing.

Early this morning the Associated Press news agency reported that hackers affiliated with Anonymous claimed to have stolen tens of thousands of encrypted military passwords from US contractor Booz Allen Hamilton and posted them on the internet.

The Pentagon said it was aware of the incident and coordinating with other federal partners on the matter.

The Press Association news agency says that Assange's lawyers are expected to argue that the alleged offences are not extraditable and sending him to Sweden would be an abuse of process and incompatible with his rights under the European convention on human rights.

They are also expected to challenge the validity of the arrest warrant and complain that it did not contain a proper, fair and accurate description of the alleged sexual misconduct.

Gareth Peirce, Assange's solicitor, has handed out the "skeleton case". On page three it reads: "Reports were filed as: i 'rape' ii 'molestation'."

Ben Emmerson, Assange's barrister, says the case against his client rests on four sex charges, and goes on to describe them in graphic detail.

The Assange team is promising not to attack his accusers and not to doubt their discomfort about his sexual conduct.

The description of the circumstances of the alleged offences in the warrant is not fair and accurate, Assange's team says, and the offences cannot be fairly characterised as rape.

Assange's team is taking a conciliatory line. They will not challenge whether the alleged victims felt he was "disrespectful, discourteous, or disturbing".

The Assange team is making a big play of the fact that the warrant fails to describe the complete complaint, and that the whole file has not been seen by them.

Assange's team says the Swedish district judge got it wrong over the charges.

The Swedish judges were misled by the wording of the arrest warrant, Ben Emmerson says.

In one case Assange is accused of having sex with a woman without a condom – but Emmerson says deceiving someone on this issue is not illegal under English law.

The Press Association has filed a first take from the court this morning. As mentioned earlier, Ben Emmerson QC told Lord Justice Thomas and Mr Justice Ouseley that the European arrest warrant under which Assange is being held was flawed because it failed to provide a "fair, accurate and proper" description of the alleged sexual misconduct.

Emmerson argued that Assange was a victim of a "philosophical and judicial mismatch" between English and Swedish law over what constituted sex crimes.

Assange's legal team is asking the judges to rule that Assange's sexual encounters with the women were "consensual" and that the alleged offences are not extraditable.

The so-called "minor rape" allegation – when Assange was alleged to have had sex with one of the alleged victims, known as SW, when she was asleep or half asleep – was an "entirely consensual sexual encounter", Emmerson says.

"He ripped her clothes and at one point ripped her necklace," Emmerson tells the court about Assange and the other alleged victim, known as AA. This alleged victim is "convinced Assange broke the condom by the glans and then continued to ejaculation", Emmerson says of AA's statement.

Emmerson stresses there was "no violence or threats", so the arrest warrant was misleading, he says.

Emmerson is now explaining the alleged victim SW's witness statement. Emmerson says:

They fell asleep and she woke up by his penetrating her. She immediately asked if he was wearing anything. He answered: "You." She said: "You better not have HIV." He said: "Of course not." She may have been upset, but she clearly consented to its [the sexual encounter's] continuation and that is a central consideration.

The thrust of the Assange team's case is that there was no lack of consent in the incidents and that the Swedish district courts were misled by the wording of the arrest warrant. Emmerson says it is "surprising and disturbing" that the warrant misled the district judges by misinterpreting witness statements.

Emmerson has told the judges that the allegations against Assange cannot amount to crimes in England and therefore extradition must be blocked. The extradition order is also flawed, he says, because it seeks Assange's return to Sweden "not for prosecution but for the purposes of an investigation" (Assange has not yet been formally charged with any offence and according to the Swedish legal system charges will only be laid after extradition and a second round of questioning).

Emmerson argues that using extradition for the purpose only of an investigation amounts to "a disproportionate utilisation" of the European arrest warrant system.

He says the court is not inquiring into the credibility of the women, SW and AA, or determining guilt or innocence. Nothing he says should be taken as condemnation of the women, he says; this is not intended to challenge "the genuineness of their feelings of regret about having had consensual sex with Mr Assange or trivialise their experiences".

Emmerson said earlier that he was not challenging the fact that they "found Mr Assange's sexual behaviour in these encounters disreputable, discourteous, disturbing or even pushing towards the boundaries of what they were comfortable with". But the sexual activities that occurred had taken place with consent, he argued, and, unlike in Sweden, could not be criminalised in the English jurisdiction.

Emmerson is arguing today that the arrest warrant against Assange inaccurately described what happened.

The four allegations against Assange are misdescribed in the arrest warrant, Emmerson says, and in all but one case would not be crimes in England.

The alleged rape by Assange when he had sex with SW when she was asleep or half asleep was not a crime, Emmerson says, because SW then consented.

The judges are wondering if they can investigate the difference between the strong wording in the arrest warrant and that of the witness statements.

The court has now broken for lunch. We will be summing up some of this morning's proceedings shortly.

Robert Booth has sent more from the high court, where proceedings are about to start again.

• Julian Assange's legal team is arguing that the European arrest warrant issued against the WikiLeaks founder is invalid, because of significant discrepancies between its allegations of sexual assault and rape and the testimonies of the two women he allegedly had sex with.

• Ben Emmerson QC told the court that the warrant – which details four allegations of unlawful coercion, sexual molestation, and rape relating to encounters between Assange and two Swedish women, known as SW and AA, on a trip to Stockholm last year – was a misinterpretation of the evidence and it was "surprising and disturbing" that Swedish district judges who requested Assange's extradition had been misled.

• Emmerson told Lord Justice Thomas and Mr Justice Ouseley that there was no evidence that there was a lack of consent in the encounters, as appeared to be suggested in the wording of the arrest warrant, and that three of the allegations would not amount to criminal offences

under English law. Referring to the allegations in the European arrest warrant, Emmerson said:

The senior district judge found that those factual allegations would establish dual criminality on the basis that lack of consent, and lack of reasonable belief in consent, may properly be inferred from the conduct described, particularly the references to "violence" and a "design" to "violate sexual integrity". However, that description of conduct is not accurate. The arrest warrant misstates the conduct and is, by that reason alone and invalid warrant.

• Of the encounter on 13 August between Assange and AA, Emmerson said:

The appellant [Assange]'s physical advances were initially welcomed but then it felt awkward since he was "rough and impatient" … They lay down in bed. AA was lying on her back and Assange was on top of her … AA felt that Assange wanted to insert his penis into her vagina directly, which she did not want since he was not wearing a condom … She did not articulate this. Instead she therefore tried to turn her hips and squeeze her legs together in order to avoid a penetration … AA tried several times to reach for a condom, which Assange had stopped her from doing by holding her arms and bending her legs open and trying to penetrate her with his penis without using a condom. AA says that she felt about to cry since she was held down and could not reach a condom and felt this could end badly.

But crucially, Emmerson said, there was no lack of consent sufficient for the unlawful coercion allegation, because "after a while Assange asked what AA was doing and why she was squeezing her legs together. AA told him that she wanted him to put a condom on before he entered her. Assange let go of AA's arms and put on a condom which AA found her."

• The case does not hinge on whether Assange accepts this version of events and others relating to other incidents because there are no charges against him, but whether the arrest warrant in connection with them is valid on "strict and narrow" legal grounds, Emmerson said.

As if to illustrate the change of strategy of Assange's new legal team, Emmerson said:

Nothing I say should be taken as denigrating the complainant, the genuineness of their feelings of regret, to trivialise their experience or to challenge whether they felt Assange's conduct was disrespectful, discourteous, disturbing or even pushing at the boundaries of what they felt comfortable with.

Assange has arrived late to the afternoon session.

The Press Association has put up a bit more from this morning's session. Ben Emmerson, Assange's QC, said that one of Assange's alleged victims described his behaviour at one point as "very strange" and talked of "just wanting" sex to be "over with". Emmerson said:

Her words may indicate she was not particularly enjoying what was going on. But they certainly do not go anywhere near what we would regard in this country as lack of consent.

He said the high court had to decide whether the "acts" would have been offences had they happened in England.

What [Swedish prosecutors] must prove beyond reasonable doubt is that if these circumstances as alleged had happened in London, would they have constituted offences? [There are] very serious questions on dual criminality in [three charges]. [There are] very serious questions on whether what happened in charge four could have recognisable as a charge in this [country].

Emmerson said there was evidence that Assange's lawyers had not seen because under Swedish law prosecutors were not obliged to reveal it until proceedings were at a later stage.

Reuters points out that permission to appeal to the supreme court if Assange loses this appeal will only be granted on a point of law considered to be of general public interest.

Lord Justice Thomas and Ben Emmerson are having an argument about the European arrest warrant regime. Should Assange see all the evidence now?

I am going to try to answer some of the most frequent questions posed below the line as we go:

Why is Assange facing extradition to Sweden when there are as yet no charges against him there?

Under the Swedish legal system, charges are laid after extradition and a second round of questioning.

Maya Wolfe-Robinson of guardian.co.uk's law site adds:

In terms of the charges in Sweden, if you read the judgment when the judge ruled that he should be extradited, the judge found that "the proceedings in Sweden are at the preliminary investigation stage. The preliminary investigation does not come to an end until evidence is served on Mr Assange or his lawyer and there is an interrogation of Mr Assange with the opportunity for further enquiries. Thereafter there is a decision as to charge. If charged the trial is likely to take place shortly thereafter.

If Assange is extradited to Sweden, and the US were then to request his extradition, what would happen to the Swedish case?

It is worth remembering that there are no extradition proceedings currently pending against Assange from the US.

I have just been speaking to Joshua Rozenberg, who writes for the Guardian's law site. Rozenberg told me that under the terms of the European arrest warrant, the Swedes would not be able to set aside their own case and pass Assange on to the US. "They are not allowed under the deal to send him to the US on other charges," Rozenberg said.

If, on the other hand, the US requested Assange's extradition while the Swedish extradition request was still being decided, the British home secretary would have to decide which request to give precedence to. Rozenberg said he thought the home secretary would be likely to favour the US, on the assumption that the charges from the US would be likely to be more serious.

In addition, Julian Knowles, a barrister at Matrix Chambers, has said that Assange's contention that he should not be extradited to Sweden because he might be extradited to the US, where he might face the death penalty or detention in Guantanamo Bay, is "frankly, a hopeless argument".

Amy Jeffress, the US justice department's attache to the American embassy in London, told the BBC's Law in Action: "The president, of course, has decided to close Guantánamo Bay, and so no one is going to Guantánamo Bay and that claim is baseless." She said the US always gave assurances in any case for which it had requested extradition that prosecutors would not seek the death penalty.

Robert Booth at the high court says the debate over the European arrest warrant has "gone into hyperspace", with Assange's barrister Ben Emmerson talking at double speed. The application could be significant though, Robert says.

The warrant must be a "fair and accurate" version of the claims, Emmerson says, and the court must ask if what is detailed there would be a crime in England, authorities say, according to Emmerson.

The Assange team thinks it is "profoundly unjust" if allegations are made to satisfy "dual criminality" test for extradition when they actually do not satisfy this test.

On the question of whether the offences a suspect is wanted for extradition for would be a crime in England, my colleague Afua Hirsch wrote this interesting piece in December:

The European arrest warrant "has been controversial since it was introduced in 2003, creating everyday injustices", Afua wrote. It was agreed a week after 9/11 and sold to voters as a way of ensuring cross-border cohesion in prosecuting suspects wanted across Europe for terrorism and serious crime.

It's been downhill from there. Around three people per day are now extradited from the UK, and there is little to suggest that the majority are terrorists or serious criminals. In fact those involved in the process agree that many of the cases are "trivial".

She goes on to say that last year Poland accounted for 40% of British extradition requests, giving the example of a case against a man who went over his overdraft limit, which would be a civil, not criminal matter in the UK.

The Assange team says the use of an EU arrest warrant for pre-prosecution questioning is not allowed under UK law.

At the high court, Robert Booth points out how dry the Assange team are "with all this legalese about EU law" – a new tack. No more shrill claims about Assange ending up in Guantanamo.

The Assange team is raising issue of "whether the requested person is an accused" and if a prosecution has "commenced". If not, then the warrant is not valid, they say.

Mark Summers, speaking for Assange, says that three weeks after the EU warrant was issued the Swedish prosecutor said "no decision to prosecute has been made in this case".

That lack of a decision to prosecute is key in undermining the validity of the Assange arrest warrant, Summers says.

Assange's "physical presence in Sweden is not necessary for finishing the preliminary investigation", says Summers, suggesting phone and Skype be used.

Here's a picture of Assange in the media scrum today, via m_cetera.

In the comments, satinsun asks what penalty Assange is facing in Sweden if found guilty. The rape charge carries a maximum sentence of four years.

Today's hearing is finished and the case will resume tomorrow.

Here are the key points:

• Julian Assange is claiming that the European arrest warrant that led to this hearing contained "fundamental misstatements" of what occurred in Stockholm last August. It falsely claims he used violence and "acted in a manner to violate sexual integrity", Assange's legal team said.

• The WikiLeaks founder's team claimed that his encounters with two women who made complaints against him involved consensual sex and would not be considered crimes in England. Ben Emmerson QC, his barrister, admitted that the women involved may have found Assange's behaviour "disreputable, discourteous, disturbing, or even pushing towards the boundaries of what they were comfortable with" – discussing, for example, Assange's initiating sex with one woman while she was asleep – but maintained that no crime had been committed under UK law.

• Emmerson also claimed that the use of the European warrant was "disproportionate", as there were other means available to obtain Assange's assistance in the Swedish investigation.

Tomorrow lawyers for the Swedish authorities are expected to argue the decision to allow Assange to be extradicted at the last stage of this legal process was correct. They will contend the EAW is nothing less than fair, accurate and proper and there is no justification for an inquiry into the validity or accuracy of the statements it contains.

Join us again tomorrow. For now, for legal reasons, we will be turning comments off – but thanks for all your contributions.