91Èȱ¬

The is designed to be one of the underpinnings of fair trials in this country. Once a prosecution is 'active' - which usually means once a suspect has been arrested or charged - the Act prevents the media publishing anything which might pose a "substantial risk of serious prejudice" to the court case which we expect to follow.

How do we square that with the way that we, the media, have covered the news that Karen Matthews, Shannon Matthews's mother, with perverting the course of justice?

Is the sort of detail that a number of newspapers are carrying - and we in the 91Èȱ¬ are to a lesser extent - compatible with her right to a fair trial? In other words, is there a danger that the twelve members of the public who'll end up sitting as jurors if the case goes ahead have already made up their minds about Karen Matthews's guilt or innocence?

I've been doing some research into this area of the law recently, and a couple of interesting trends emerge.

First, judges seem more and more willing to believe that juries will disregard press coverage that they might have seen around the time that someone is arrested. In fact, they think jurors will probably have forgotten about it by the time the case comes to trial.

It's what's known as the 'fade factor'. If it exists - and no-one really knows because there's been no research to speak of - it might mean that a fair trial can take place in a few months' time regardless of what's said or printed now.

But it's got a serious downside, of course. If you're the suspect in a case, and you have to sit around for months, possibly on remand, while the rest of us forget about all those details which were published when you were arrested, that might not seem entirely fair to you.

The second interesting phenomenon is the effect of the internet. At the moment the law is based on the notion that we can create the conditions for a fair trial by denying people certain important pieces of information. So, for example, if people have previous convictions, we don't report that after they're arrested.

But what if you can't deny people that information any more?

If you're a juror sitting on a high-profile criminal trial your curiosity might lead you to check whether the alleged villain in the dock has a long criminal record. You could find that information very quickly on the internet - and, remember, it's information which would have been published perfectly properly at the time.

Can we stop that happening? Judges will certainly warn jurors not to do it, but that's no guarantee. Ministers have suggested that news organisations should take down their archive pages to stop people accessing information that might currently be considered prejudicial, but those pages are mirrored and cached all over the place. The idea of removing old news pages from everywhere on the web seems deeply impractical.

So what we have now is an Act based on two suppositions, one of which is unproven, and the other of which is increasingly undermined by the internet.

The first is that, within the jury room, jurors might be swayed by things they've read, seen or heard in the media. There's no real evidence that this is true - and judges, increasingly, seem to take the view that juries are capable of making up their minds based on what they've heard in court.

The second is the whole idea that we can withhold entire categories of information to make a fair trial possible. The internet does away with that: if 'prejudicial' information has been published, we can't un-publish it.

This isn't an argument for a press free-for-all. If everything we report can resurface in this way it's even more important that it should be fair and accurate.

But it does mean, I think, that whether we like it or not we have to trust juries more than the current law implies. And probably it requires a new law to do that.