Julian Assange will, according to the judge's finding of fact, be held in prison in solitary confinement when he is returned to Sweden and will then be interrogated, held without bail and later subjected to a secret trial on accusations that have been bruited around the world, not least by this newspaper. He has a complete answer to these charges, which he considers false and baseless. Even if acquitted, however, the mud will stick and, if convicted, the public will never be able to able to assess whether justice has miscarried. This country, which has given to the world the most basic principles of a fair trial – that justice must be seen to be done – denies that basic liberty for those that are extradited to Sweden.

How come our courts abandon our cherished principles in deference to European systems and prosecutors? The answer is that they are bound to regard the prosecutors of no less than 26 countries, including Poland and Romania – as perfect. This is the result of the European arrest warrant (EAW), one of the civil liberties disasters bequeathed by the Labour government when it passed the Extradition Act in 2003.

This act, quite incredibly, allows European countries to deem prosecutors and even policemen "as judicial authorities" (a contradiction in terms, because they are neither independent nor impartial) and to pluck their suspects from the UK so long as they tick the right box on the EAW form. In Assange's case, for example, they ticked "rape" and the court cannot dispute that the allegation is of rape, even though the leading authority on sexual offences, the Oxford Vinerian professor, Andrew Ashworth, disputes this characterisation. There can be no questioning on the merits of the charges – in 2003 parliament abolished the traditional right of a suspect to require foreign governments to show a prima facie case before dragging them off to unfair trials.

An inquiry into the working of the EAW system has been set up and Assange's appeal to the high court may demonstrate the extent to which it allows our judges to stand up against unfair European systems. In the case of Sweden, for all its civilised and rational approach to many criminal justice issues – especially sentencing – it is a human rights black spot in relation to solitary confinement, the lack of a money-bail system and ill-treatment of foreigners in the very prison for which Assange may be destined – all matters for which it has been condemned by the recent European Committee report on torture.

But nothing so breaches the most fundamental principle of justice as its custom of holding all rape trials behind closed doors. This, so the prosecutor Marianne Ny explains, is so that "complainants may give their evidence better". Of course it is absolutely right to give complainants the protection of anonymity and to limit the right to cross examine them on their past, but it is utterly wrong to keep it from public view, for three reasons:

1. As Jeremy Bentham pointed out, "publicity is the very soil of justice, it keeps the judge, while trying, under trial". In this case, which will be heard by three lay judges appointed by political parties who are usually members of such parties, it is essential to see justice being done, especially since the Swedish prime minister has publicly attacked Assange.

2. Second, openness is essential to truth. It ensures that witnesses will be afraid to perjure themselves less they be found out. Others will come forward to confound them if they learn that they are lying. In this case, where both complainants tweeted and text-messaged their friends in ways which can be said to be inconsistent with their complaint, justice demands a public hearing.

3. Finally, the public itself has an interest, and that must override the interest of individuals whether the complainant or even defendants are happy that their details of conduct are hidden from public view. No democracy can commit secret court, because then there is no check that the formidable powers of prosecutors and judges are not being abused.

There are two philosophic approaches to the EAWs open to our courts. At present most adopt the "rubber stamp" approach – hand suspects over to the European policeman and prosecutors if the formalities on the warrant are correct. But the alternative – which we will invite the high court to adopt in this case – is that the EAW system should be used to actually improve the quality of justice throughout Europe, but to refuse extradition when the trial in prospect is likely to be unfair, judged according to our fundamental principles. That way, things can only improve and human rights blind spots can be eradicated. If our courts declare that open justice is the only possible justice by denying Sweden the extradition of Assange, this would very likely have the result that Sweden would change its unacceptable policy.

Open justice is one of the greatest contributions the UK has made to international human rights law. It goes back to the famous demand of "freeborn John Lilburne the leveller" – to have the doors of his court opened so that Cromwell's judges could not try him in "holes or corner". The rhetoric about the importance of open justice is found throughout law reports and often in cases brought by journalists at newspapers like this one. Will all this judicial rhetoric be empty or even hypocritical when it comes to deporting Julian Assange? We must wait and see.

• The author is legally representing Julian Assange