Lessons from the Lawrence trial in unbiased juries There can't be many people who did not, at some moment in recent weeks, reflect on the position of the jury in the Stephen Lawrence murder trial. Here were 12 ordinary citizens hearing evidence about one of the most notorious crimes of the past generation: how would they arrive at a verdict without feeling the weight of all that public emotion upon their shoulders? In the court of public opinion, after all, the defendants - Gary Dobson and David Norris - had long ago been convicted, with three others, of this racist killing. The Daily Mail had called them murderers on its front page. The BBC had broadcast a programme entitled The boys who murdered Stephen Lawrence. Among thousands of other reports and publications over the years is a book by me, which also painted them in an extremely sinister light. Against such a background it was - and is - reasonable to ask whether jurors could genuinely "put from their minds," as the judges ask, everything they have read and heard, and reach their verdicts on the evidence alone. The answer of the courts is that everything was done to ensure that they could, indeed the authorities went to unusual lengths. For example, for several months there was a news blackout on the case, with court orders forbidding the media to report that arrests had been made and a prosecution was imminent. As proceedings approached, editors were strongly reminded of the sub judice rules and the need to avoid prejudicing potential jury members. When it came to the selection of the jury, the judge, Mr Justice Treacy, excluded anyone from south-east London, where the murder took place, and also anyone with a more than general awareness of the case. Once the 12 were chosen, they were emphatically warned not to engage in independent research. As for the seven weeks of proceedings, they appear to have been low on emotion and studiously focused on forensic detail. At the conclusion the judge warned jurors to set feelings aside and rely on facts, and he issued a remarkable written "route to verdict," laying out not only what questions they had to answer, but in what order and on the basis of what evidence. No effort was spared, in other words, to ensure that these defendants received a fair trial despite all the baggage attached to the case, and no doubt it is a measure of the success of those efforts that the defence did not make an issue of possible jury prejudice. And yet we don't know that prejudice did not play a part. Juries in general are constantly asked whether they are "sure" of things. Are you sure that the defendant was present at the scene? Are you sure that the identification evidence is reliable? Are you sure that the forensic scientists were correct? So, are we sure that the jury in this case was not influenced by the weight of public opinion? The answer must be no because, by law, we can't interrogate them. Of course, none of us wants to see such interrogations -- the secrecy of the jury system is a popular principle and the idea of jurors granting public interviews after verdicts is repulsive. A problem remains, however: when it comes to how far juries in general in this country might be influenced by media coverage, we rely too heavily on trust. Because of the legal constraints, meaningful research is difficult and such work as has been done leaves us considerably less than "sure." A general investigation of jury bias two years ago by Cheryl Thomas of University College London provided a measure of reassurance but found that in high-profile cases, a fifth of jurors admitted to difficulties in putting media coverage out of their minds. That is surely a cause for concern. The issue is often debated, none the less, because it matters. Mr Dobson and Mr Norris, for all their notoriety, were entitled to the fairest possible trial. Anything less would have been a betrayal of the idea of justice for the Lawrence family. That Dobson could only be tried because the historic double jeopardy rule has recently been abandoned - in part because of the Lawrence case itself - underlines the point. Significantly, great caution is now exercised there too, and the bar for retrying a person previously acquitted is set very high. The implications of possible media prejudice go far wider than this one case. Only last summer Dominic Grieve, the Attorney General, argued in court that some of the reporting of the arrest of Christopher Jefferies, who turned out to be wholly innocent of the murder of Joanna Yeates, would have prejudiced his chances of a fair trial. I followed closely the trial of Barry George, wrongly convicted of the 1999 murder of Jill Dando and eventually freed on appeal. So weak was the case against him that I am convinced the lurid media reporting at the time of his arrest influenced the original verdict. This problem gains urgency because of the internet. Jurors are now able to Google a defendant's name on their phones and it is clear that, despite ever sterner warnings from judges, some do not resist the temptation. They may read archive media coverage as a trial progresses, learning of previous convictions, malicious gossip and material declared inadmissible by the judge. Judges answer that we should trust them and trust juries. They speak of a "fade factor" - press coverage at the time of arrest is often forgotten by the time a trial comes along - and a "focus effect" - juries tend to concentrate on the evidence presented in court. Judges also take pride in their own power to steer juries away from prejudice. The truth is that everyone is bluffing. Just as it is impossible to prove that any conviction - including those of Mr Dobson and Mr Norris - is free from prejudice, it is also impossible to prove the effectiveness of fade, focus and judges" directions. We urgently need more to go on, more research and more scholarship. We need to know more, in a general way, about the thinking of juries, and not just what they say but how they interact in real cases, and what subtle effects previous and current media coverage can have. This means breaching the secrecy of the jury room, though within the bounds of academic confidentiality. If we value jury trial and want to maintain its integrity, that is surely a price worth paying. The writer is professor of journalism at Kingston University and author of The Case of Stephen Lawrence