Strange things may well go on in the country's jury rooms. No one knows, but we get glimpses. One conviction was quashed when it emerged that a jury consulted a Ouija board during their deliberations. In 2005 the Court of Appeal quashed a rape conviction based not so much on what was done but on what might have been read by a juror.

After the guilty verdict at Canterbury Crown Court an eagle-eyed court bailiff spotted documents downloaded from the internet lying around the jury room. One was entitled The Feminist Position on Rape, the other Rape and the Criminal Justice System. The appeal court took the view that the material was capable of encouraging the uncritical acceptance of evidence from the rape victim. No inquiries were made as to the circumstances in which the documents were downloaded and yet the conviction was quashed and a retrial ordered. The case goes to the heart of the uneasy relationship between technology and the law. It prompts the question: has the internet rendered a large chunk of our contempt law dead?

The Contempt of Court Act 1981 was drafted at a time when the internet of today was a mere cyber-twinkle. The Act essentially prohibits the media from writing or broadcasting anything that represents a substantial risk of seriously prejudicing the course of public justice. But in an age when anyone can write just about anything on a blog or online discussion board without any real fear of prosecution, why is the law still enforced - well, sort of enforced - against newspapers and broadcasters?

The reasoning behind the 1981 Act is clear and laudable. The minds of jurors should be unsullied by the polluting effects of prejudicial information. For instance, prior knowledge of a defendant's previous convictions should not colour their thinking about a present accusation. But there has always been a problem here. Newspapers are perfectly entitled to publish details of a crime, including previous convictions of a suspect, before an arrest. Contempt only kicks in when court proceedings become “live”. Anyone wanting to search a traditional newspaper archive has always had access to prejudicial information.

Some countries just don't see all this as a risk. In America jurors can digest prejudicial material on television, the internet or anywhere else. The justice system there has faith in their ability to take strong direction from the trial judge that they must assess the case solely on the evidence. If there is a risk of prejudice, the jury can be sequestered.

So, is our system superior, purer as a result of our contempt law? It's difficult to tell if jurors are influenced by the media as it is also a contempt here to research what influences jury decision-making. Foreign research on the effects of pre-trial publicity is contradictory. But, interestingly, researchers in Australia found that any media reports were unlikely to be remembered in detail, and anyway they were superseded by evidence heard at the trial and by the jury's own deliberations.

For our current law to be respected it needs to be seen to be effective. But prosecutions of newspapers and broadcasters by the Attorney-General are few and far between. Lord Goldsmith issued a warning to the media over coverage of the Soham murders; yet no one was prosecuted. The last newspaper editor to go to prison was in 1949. Today's ever-increasing demand for information and speculation in big cases, such as the Rhys Jones murder, has led the print media in particular to push at the limits of what is permissible. If they don't, their readers can always go into the unregulated blogosphere for news.

Today the law can only be effective if it can police the wild, untamed internet. Lord Falconer of Thoroton recently suggested that newspapers and broadcasters should go back and delete contemptuous material from their online archives if a matter they have reported on goes to trial. But would it work? Material from online archives can easily be copied on to other web pages. To get it removed the Attorney might have to chase it as it leapfrogs from website to website. But removal is nigh on impossible. Invisible copies are stored elsewhere in cyber-caches, and they would remain even if a broadcaster deleted material from its archive. There is also nothing to stop anyone abroad setting up Contempt.com and publish away happily beyond the reach of our law.

Is it possible for the Attorney General to keep a finger in the cyberspace dyke? Many criminal lawyers believe it isn't and that it's time to do away with an ineffective contempt law. Jurors, even if they are cyber savvy, should be trusted to do what they are charged to do by the judge: listen to the evidence and bring in a verdict based on it alone. If that doesn't happen, our contempt law itself risks being held in contempt.

Clive Coleman is a barrister and the presenter of Radio 4's Law in Action

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