Julian Assange today takes his argument against extradition to Sweden to the UK Supreme Court. The hearing is due to finish tomorrow – it’s not clear yet when the Court is likely to publish its judgment.

There’s one question only being argued before the Supreme Court: whether the Swedish prosecutor is a judicial authority for the purposes of Part 1 of the Extradition Act 2003, which gives effect to the European Arrest Warrant system. All his other legal arguments – including the argument that the European Arrest Warrant against him is invalid because he’s not been charged – have been defeated and are no longer in dispute.

Thanks to the Guardian, we can read Assange’s arguments on the judicial authority point:

The argument looks attractive superficially (as written submissions usually do when read in isolation), but in reality it’s pretty thin. Dinah Rose QC, for Assange, makes much of the fundamental principle that a prosecutor cannot be a judge in its own cause, and argues that case law under the European Convention on Human Rights strongly supports that principle. But the argument is deeply problematic: the ECHR does not and cannot lay down a general principle that prosecutors can’t count as judicial authorities for any purposes whatever throughout Europe.

The case law Dinah Rose cites in support of her client shows us a prosecutor isn’t sufficiently independent to order Assange’s detention under article 5 of the Convention. A prosecutor wouldn’t be sufficiently independent to determine civil rights or criminal charges under article 6. But the Swedish prosecutor in this case has neither ordered Assange’s detention (that has been authorised by a court in both countries) nor purported to determine any charge against him. Assange’s argument does not establish the link between the requirements of the Convention and the issuing of the European Arrest Warrant that would in my view be needed in order for the human rights principles he draws on to govern the Court’s interpretation of the concept of judicial authority. It’s this missing link that I think is the fatal flaw.

Assange’s argument is hopeless – I expect him to lose and, as I’ve been saying for the last year, I expect him eventually to face justice in Sweden.

He may apply to the European Court of Human Rights and try to obtain “interim measures” preventing his immediate surrender to Sweden – but since it’s unclear on what basis he can argue his extradition or prosecution would breach the Convention at all, and since there can be no serious suggestion that Swedish justice would amount to a flagrant denial of justice, I’ll be astonished if he achieves that.

He could be in Sweden by Easter.