Good morning. The supreme court will rule this morning on whether Julian Assange should be extradited to Sweden to face allegations of rape and sexual assault. The WikiLeaks founder denies the accusations.

The judgment will be announced at 9.15am. Lord Phillips of Worth Matravers, the president of the supreme court, will give a summary of the point of law raised by the case, the court's decision, and a brief explanation of why it has reached that decision.

Today's ruling does not deal with the substance of the accusations – which relate to a trip Assange took to Sweden in 2010, after which he was accused by two women with whom he had had sex of four offences of unlawful coercion and sexual misconduct including rape.

Instead it relates to one specific question: can a prosecutor rather than a judge legally order someone's extradition?

In Britain generally only judges can approve arrest warrants. But the warrant for Assange was issued by Sweden's public prosecutor, as is normal there.

Assange's lawyers argue that the Swedish system is unfair because it puts the power to issue arrest warrants in the hands of the same prosecutors who are trying to put the accused person in jail.

After a court ruled in February 2011 that Assange should be sent to Sweden to answer the accusations against him, the WikiLeaks founder appealed, lost, and then took the case to the supreme court. This February the supreme court heard two days of dense legal argument about whether a Swedish prosecutor constitutes a judicial authority under the European arrest warrant framework and the Extradition Act 2003, which incorporates it into British law, along with discussions of the history of the European arrest warrant framework going back to the 1957 European convention on extradition. (I live-blogged those two sessions in exhaustive detail here and here.)

Assange's QC, Dinah Rose, argued that the European arrest warrant's use of the term "judicial authorities" was meant to mean a judge or magistrate, and not a prosecutor, who is not independent. For Sweden, Clare Montgomery QC argued that the term "judicial authorities" was always meant to encompass prosecutors in some EU countries, and there was no requirement for the figure issuing the warrant to be independent.

If Assange loses today he can appeal to the European court of human rights. The ECHR will then respond within 14 days.

If it decides to take the case, it can also order "interim measures" to stay Assange's extradition until the case is heard.

However, the Crown Prosecution Service says that if the ECHR agrees to take the case it will not extradite him until the case has been heard, with or without interim measures: "If the ECHR takes the case then his current bail conditions would remain in force and he would remain in the UK until the proceedings at the ECHR have concluded." That could be months away.

However, it seems unlikely that the ECHR would agree to take the case. Barrister Carl Gardner of the Head of Legal blog told the Guardian that such an application would be a "steeply uphill" struggle for Assange:

His argument could only be that extradition (an application against the UK would have to be about the extradition itself) would breach article six [of the European convention on human rights – the right to a fair trial] indirectly, because a trial in Sweden would be a "flagrant denial of justice" - more than just an ordinary unfair trial. The only time I think the ECHR has ever said extradition/deportation/removal on these grounds would be in breach is I think Abu Qatada's case this year, in which it said the risk of use of evidence gained by torture would be a flagrant denial of justice. Assange's complaint would be much less powerful than that.

Assange may choose not to appeal to the ECHR. A source close to the WikiLeaks founder told the Guardian during February's supreme court hearings that he was unlikely to do so.

If the ECHR refuses to take the case Assange will be extradited to Sweden "as soon as arrangements can be made", the CPS says. Once in Sweden, Assange would probably be kept in custody - bail does not exist there - and if he is charged a trial might begin in a few months.

If Assange wins, however, he will not be extradited, and the system of European arrest warrants will be thrown into doubt, because many European countries have a system similar to Sweden's.

You can read more about the background to the case here.

Footage of the proceedings will be streamed live here. My colleagues Owen Bowcott and Esther Addley will be tweeting live from court, and we will be covering everything live here on this blog.

Karen Todner of Kaim Todner Solicitors, which has fought many extradition cases, has told the Associated Press she thinks Assange's prospects of success have increased:

When he first started out, I thought: "He hasn't gotten much of a chance," but now I'm much more hopeful. I would say that in the last few months there has definitely been a swing in favor of defendants in relation to extradition.

But she suggested that if Assange wins Sweden could reissue the extradition warrant through a judge.

And a spokewoman for Sweden's prosecutors told Reuters that if he wins the Swedish arrest warrant will still be valid in any other European country bar Britain.

In Stockholm, former senior prosecutor Sven-Erik Alhem expressed frustration with the delays, saying that European arrest warrants "should work efficiently and rapidly" and that he was surprised that the legal wrangling in Britain had dragged on for a year and a half. "If I were in his shoes, I would have been going to Sweden at once to get rid of this horrible situation where an investigation has been going on for so long," Alhem said.

Esther Addley tweets from the supreme court:

Team #Assange - Vaughan Smith, Gavin McFadyen, John Pilger, Kristin Hrafnsson - arrive at court. I haven't seen JA tho assume he's here — esther addley (@estheraddley) May 30, 2012

Owen Bowcott tweets from the supreme court:

More cameras than pro-Assange demonstrators outside. Usual Rolls Royce service inside supreme ct as machinery of justice glides into place. — Owen Bowcott (@owenbowcott) May 30, 2012

Esther Addley tweets from court:

20-30 journalists in court, all on laptops, iPads, smartphones. Similar scene on public benches too, obv. #Assange — esther addley (@estheraddley) May 30, 2012

The live feed from the supreme court has begun. You can watch it here.

BBC News is showing pictures of pro-Assange supporters outside the supreme court, carrying placards backing the WikiLeaks founder.

Dinah Rose QC and Assange's legal team are taking their seats.

All rise as the justices enter the court.

Lord Phillips of Worth Matravers, the president of the supreme court, begins speaking.

He says the Swedish extradition request has raised a point of law for the court to address. That has nothing to do with the actual accusations against Assange, he says.

Phillips runs through the brief recent history of the European arrest warrant system.

This introduced a new rule whereby the state requesting extradition no longer had to prove the case to the other state.

Phillips says the point of law - does a prosecutor have the right to order extradition or must that be done by a judge - had not been simple to resolve and the decision on the supreme court was 5-2.

In French the words judicial authority can be used to mean a public prosecutor, Phillips says. Many countries use public prosecutors. The majority of justices agree that this means a public prosecutor is included in the Extradition Act.

Lady Hale and Lord Mance did not agree, he says.

That means Julian Assange has lost his case.

The Swedish public prosecutor is a judicial authority. The request for Assange's extradition has been lawfully made and his appeal has been dismissed, Phillips says.

Dinah Rose QC, for Julian Assange, says she has not had time to study the decision properly yet but she says it means that a majority of members of this court have made their decision based on the Vienna Convention on the Law of Treaties - but that was never brought up at the time, she says.

She is considering an application to argue that this matter should be "reopened", Rose says.

Lord Phillips gives her two weeks to make an application to reopen this case.

Rose asks if the extradition can be stayed for two weeks too. Phillips says that is a reasonable request and grants that.

Assange was not in court today.

The supreme court has just sent its full judgment. The press statement reads:

The issue is whether an European arrest warrant ("EAW") issued by a public prosecutor is a valid Part 1 EAW issued by a "judicial authority" for the purpose and within the meaning of sections 2 and 66 of the Extradition Act 2003. By a majority the court has concluded that the Swedish public prosecutor was a "judicial authority" within the meaning of both the framework decision and the Extradition Act. It follows that the request for Mr Assange's extradition has been lawfully made and his appeal against extradition is accordingly dismissed.

It adds:

The supreme court by a majority of five to two (Lady Hale and Lord Mance dissenting) dismisses the appeal and holds that an EAW issued by a public prosecutor is a valid Part 1 warrant issued by a judicial authority within the meaning of section 2(2) and 66 of the 2003 Act.

Here are the supreme court's reasons for its judgment:

Article 34 (2)(b) of the Treaty on European Union provides that framework decisions are binding on member states as to the result to be achieved but that national authorities may choose the form and method of achieving this. For the reasons given by Lord Mance in his judgment the supreme court is not bound as a matter of European law to interpret Part 1 of the 2003 [Extradition] Act in a manner which accords with the framework decision, but the majority held that the court should do so in this case. The immediate objective of the framework decision was to create a single system for achieving the surrender of those accused or convicted of serious criminal offences and this required a uniform interpretation of the phrase "judicial authority". There was a strong domestic presumption in favour of interpreting a statute in a way which did not place the United Kingdom in breach of its international obligations. An earlier draft of the framework decision would have put the question in this appeal beyond doubt, because it stated expressly that a prosecutor was a judicial authority. That statement had been removed in the final version. In considering the background to this change, the majority concluded that the intention had not been to restrict the meaning of judicial authority to a judge. They relied, as an aid to interpretation, on the subsequent practice in the application of the treaty which established the agreement of the parties. Some 11 member states had designated public prosecutors as the competent judicial authority authorised to issue EAWs. Subsequent reviews of the working of the EAW submitted to the European council reported on the issue of the EAWs by prosecutors without adverse comment and on occasion with express approval. Lord Phillips felt that this conclusion was supported by a number of additional reasons: (1) that the intention to make a radical change to restrict the power to issue EAWs to a judge would have been made express, (2) that the significant safeguard against the improper use of EAWs lay in the preceding process of the issue of the domestic warrant which formed the basis for the EAW, (3) that the reason for the change was rather to widen the scope to cover some existing procedures in member states which did not involve judges or prosecutors and that the draft referred to "competent judicial authority" which envisaged different types of judicial authority involved in the process of executing the warrant. Lord Dyson preferred not to infer the reasons for the change and did not find the additional reasons persuasive. Lord Walker and Lord Brown also found these reasons less compelling. Lord Kerr relied on the fact that public prosecutors in many of the member states had traditionally issued arrest warrants to secure extradition and a substantial adjustment to administrative practices would have been required. Parliamentary material relating to the debates before the enactment of the 2003 Act were held by the majority to be inadmissible as an aid to construction under the rule in Pepper v Hart [1993] AC 593, given the need to ensure that the phrase "judicial authority" had the same meaning as it had in the framework decision. Lord Kerr remarked that that it would be astonishing if parliament had intended radically to limit the new arrangements (thereby debarring extradition from a number of member states) by use of precisely the same term as that employed in the framework decision. Lord Mance, dissenting, held that the common law presumption that parliament intends to give effect to the UK's international obligations was always subject to the will of parliament as expressed in the language of the statute. In this case, the correct interpretation of "judicial authority" in the framework decision, a question of EU law, was far from certain. Thus if parliament had intended to restrict the power to issue EAWs to judges or courts, that would not have required a deliberate intention to legislate inconsistently with the framework decision. As the words in the statute were ambiguous, it was appropriate to have regard to ministerial statements, and those statements showed that repeated assurances were given that an issuing judicial authority would have to be a court, judge or magistrate. Lady Hale agreed with Lord Mance that the meaning of the framework decision was unclear and that the supreme court should not construe a UK statute contrary both to its natural meaning and to the evidence of what parliament thought it was doing at the time.

Here is the judgment in full (pdf).

Legal commentator Joshua Rozenberg was just on BBC News talking about the request by Julian Assange's QC, Dinah Rose, for two weeks to decide whether to ask the supreme court to reopen the case. He said:

This is a very unusual thing. It's not happened since this court was set up. It happened in the Pinochet case in the House of Lords. Very unusual, and means there's everything left to play for still.

He said that since Assange was not in court his lawyers had not been able to take instructions from him yet regarding what he wanted them to do. "We're waiting to see what he says. In the meantime he can stay in this country for at least two weeks, while they consider making this unprecedented application to reopen the case on the basis that it was decided on a point of law in the Vienna Convention on the Interpretation of Treaties that was simply not argued by either side and which the court gave no notice to either the Crown Prosecution Service, representing the Swedish authorities, or Mr Assange's lawyers, that they were considering taking into account."

Rozenberg added:

It would be very embarrassing if the supreme court felt the need to reopen the case and it's extraordinary, isn't it, that they might have considered something which they gave the parties no opportunity to argue. From time to time judges do their research and they add points, minor points, that have not been considered, but it appears that the decisive point in this case was one that wasn't argued, and that's something which is pretty unusual, and that's what prompted this unexpected intervention from Dinah Rose which took Lord Phillips so much by surprise that he mixed her up with the other counsel, Clare Montgomery.

Here is a summary of this morning's events:

• Julian Assange has lost his appeal against extradition to Sweden at the supreme court. By a majority of five to two, the justices decided that a public prosecutor was a "judicial authority" and that his arrest warrant therefore had been lawfully issued.

• But lawyers for the WikiLeaks founder were given two weeks to decide whether to challenge one of the points made in the judgment, and Assange's extradition will be stayed at least until then. Dinah Rose QC, for Assange, said that the justices had made their decision based on the Vienna Convention on the Law of Treaties - but the provisions of that convention had not been raised during the hearing.

• Legal commentator Joshua Rozenberg said this meant there was "everything to play for still", and it would be "very embarrassing" if the supreme court had to reopen the case on the basis that "they might have considered something which they gave the parties no opportunity to argue".

• In brief, the judges ruled that the the UK had signed up to the European framework on extradition in order to help create a single system for surrendering accused people, and that it was always intended that the 11 EU member states that allow prosecutors to issue extradition orders – as Sweden, but not the UK, does – would be able to continue doing so.

• Lord Mance, one of two dissenting justices, said the wording of the framework decision was ambiguous and so it was appropriate to consider what ministers said at the time, which was that it would be a judge, court or magistrate that issued the order.

• Assange was not in court. His solicitor, Gareth Peirce, told the Guardian's Owen Bowcott that he was stuck in traffic.

My colleague Esther Addley has been speaking to Gareth Peirce, Julian Assange's lawyer.

Peirce said that Assange's team will ask the supreme court to reopen the case based on the fact that the justices made their decision based on the Vienna Convention on the Law of Treaties, which was not discussed in court.

If that fails, Assange's supporter John Pilger, the Australian journalist, told Esther that his team would appeal to the European court of human rights.

Peirce told her it was premature to say that before domestic legal routes had been exhausted. "It's fair to say that the mood within the Assange camp is to take this as far as they can," Esther said.

The supreme court has just put out this statement:

Following this morning's judgment by the supreme court of the United Kingdom in Assange v The Swedish Prosecution Authority, Ms Rose (counsel for the appellant, Mr Assange) has indicated that she may make an application to reopen the court's decision. Ms Rose suggested that the majority of the court appear to have based their decision on the interpretation of the Vienna Convention on the Law of Treaties, on which no argument was heard and no opportunity of making submission was given. The supreme court has granted Ms Rose fourteen (14) days to make such an application. If she decides to do so, the justices will then decide whether to reopen the appeal and accept further submissions (either verbally through a further hearing, or on paper) on the matter. We will keep you updated on progress with this application and the justices' consideration of any such application. With the agreement of the respondent, the required period for extradition shall not commence until 13 June 2012, the 14th day after judgment in accordance with section 36(3)(b) of the Extradition Act 2003.

The full judgment makes several references to the Vienna Convention on the Law of Treaties (to recap, Assange's team plan to ask the supreme court to reopen the case now because this convention was not discussed during the supreme court hearing in February). The convention was adopted in 1969 and codifies the principles of international treaties.

• On page 25 of today's judgment, Lord Phillips, the president of the supreme court, notes that the convention allows judges to consider how a treaty has been implemented in practice in order to interpret its intentions. He uses this principle to point out that EU member states, the European commission and European council have all acted as if the extradition agreement allowed prosecutors to issue extradition orders.

• On page 49, Lord Walker says he finds the above point "determinative" in his rejection of Assange's case. On page 53, Lord Kerr also uses the Vienna convention as evidence in rejecting Assange's case. Lord Dyson does the same on page 61.

• However, on page 77, Lady Hale, one of the dissenting justices, makes some points which may be similar to any case Assange's team may make if the case is reopened. Hale notes:

Article 31.3(b) of the Vienna Convention on the Law of Treaties provides that there shall be taken into account, along with the context, "any subsequent practice in the application of the treaty which establishes the agreement of the parties regarding its interpretation". While the practice need not be that of all the parties to the treaty (as in this case it obviously is not) the practice has to be such as to establish the agreement of all the parties as to its interpretation. Given the lack of common or concordant practice between the parties, is the failure to date of those countries which do not authorise prosecutors and other bodies to object to those who do sufficient to establish their agreement? Nobody in this country seems to have addressed their mind to the issue until it arose in this case. Failure to address minds to an issue is not the same as acquiescence in a particular state of affairs. Subsequent practice does not give support to the respondent's extreme position and there has been no consideration of the principles which might distinguish some prosecutors from others. This seems to me to be a rather flimsy basis on which to hold that we are obliged to construe a United Kingdom statute contrary both to its natural meaning and to the clear evidence of what parliament thought that it was doing at the time.

• And on page 94 Lord Mance claims "suspect practice consisting of the use and nomination of executive authorities by a few states cannot come near establishing 'the agreement of the parties regarding [the] interpretation of the Framework Decision' within the meaning of article 31.3 of the Vienna Convention on the Law of Treaties."

So it seems there is plenty of scope for legal argument on this point should the case now be reopened.

Jago Russell of campaign group Fair Trials International has attacked Sweden over its use of pre-trial detention. Russell said: "Although Sweden is rightly proud of its justice system, its overuse of pre-trial detention means that, if extradited, he is likely to be imprisoned and placed under extremely restrictive conditions."

The charity also summarised what would happen to Assange if he is extradited:

Mr Assange will be arrested on his arrival in Sweden and taken to a Swedish police station. Within 96 hours of being detained he will be brought to court, for a decision as to whether he should be remanded in custody until trial … This hearing is normally in private, unlike in many other countries, including the UK, where such hearings are normally in open court. As soon as the investigation is over, a decision will be taken about whether to formally charge him. Swedish law requires a person to be physically present before charges can be laid, so this can only happen once Mr Assange is on Swedish territory. Alternatively, prosecutors may decide not to charge Mr Assange and to release him.

Fair Trials International is calling for reform of the European arrest warrant system to guard against its "abuse and overuse" and wants the EU to legislate "to require all EU countries to respect basic fair trial rights and ensure people are not kept in pre-trial detention for excessive periods".

Here is a clip from this morning's hearing.

A Liberal Democrat peer and MEP has attacked the length of Julian Assange's court case.

Lady (Sarah) Ludford, MEP for London, says that one of the positive aspects of the European arrest warrant is its "making extradition to trial quicker and less bureaucratic." But:

Lengthy court proceedings like this on procedural issues however defeat the objective, with justice delayed being justice denied. It might therefore be helpful if EU legislation was clearer on definitions such as "judicial authority", although it is difficult to do so without encroaching on national competence for criminal justice systems.

She says she is going to ask her fellow MEPs to raise the judgment with the European commission and the European council.

Here is the Guardian's interactive history of the supreme court.

WikiLeaks spokesman Kristinn Hrafnsson has blamed Washington for today's ruling. "This is not the final outcome. What we have here is retribution from the US," he said, according to Reuters.

Claes Borgstrom, the lawyer who represents the two Swedish women who accuse Assange of sex crimes, dismissed such claims in comments to the Associated Press. "He is not at a greater risk of being handed over from Sweden than from Britain," Borgstrom said.

Per Samuelson, one of Assange's two Swedish lawyers, said he was confident his client would be cleared if he had to go to Sweden. "I feel a strong conviction that he will, in Sweden, in due time, one way or another, be vindicated - he will be exculpated and acquitted ... I look forward to this with confidence," he told Reuters.

My colleague Owen Bowcott reports that Assange's lawyers can begin appealing against the judgment to the European court of human rights at the same time as requesting the supreme court reopen the case.

Joshua Rozenberg has the inside story on how Dinah Rose's "quick legal footwork" ensured Julian Assange a two-week stay of extradition this morning.

The judges had been warned that Dinah Rose QC, his fearless counsel, wanted to address the court. But they were not prepared for what she had to say. That was largely their own fault. Normally, draft judgments are circulated to counsel up to a week before delivery. That enables the lawyers to point out minor errors: a name mistyped, a date wrong and so on. It's something of a safeguard for the judges. But since it was the WikiLeaks man whose appeal they were hearing, the supreme court justices were taking no chances. To avoid leaks, lawyers were not shown the judgments until 8.30 this morning. That was just enough time for Rose to work out that the court had based its reasoning on a point that had never been argued at the two-day hearing in February. Assange, who didn't turn up for the judgment, knew nothing of what was being done on his behalf.

He also gives a rough summary of what might happen when Assange's team asks the supreme court to reopen the case:

In the end, the judges may decide that they were entitled to take the Vienna convention into account. In that event, they would presumably confirm the decision they delivered today. But given two weeks to prepare her case, Rose could well come up with other arguments. In the meantime, Assange can stay in the UK.

Julian Assange's lawyer Gareth Peirce is quoted in this story by Owen Bowcott and Esther Addley:

The majority of the judges believe that parliament was seriously misled when it approved the European arrest warrant system. Parliament thought a "judicial authority" meant a judge or court but the majority of supreme court judges based their decision on what is the practice in Europe and decided it on the basis of the Vienna convention, which was never argued before the court.

Veteran Australian journalist John Pilger, a supporter of Assange's, was also quoted. He was putting a brave face on today's events:

I don't think this judgment is a blow. We are disappointed but it came so close. Three of the judges [who found against Assange] were tipping in our favour. There was a consensus [on the bench] that parliament had been misled on this law. The court has now agreed to allow Julian Assange's legal team to go back and reconsider this. This case moves in mysterious ways and we are about to move into another mysterious stage of this whole unnecessary process.

.

With that I'm going to draw this blog to a close. Many thanks for all your comments. See you next time.

One final post. Here Julian Assange's supporters and his lawyer react to today's verdict.