The discomfort that the OJ Simpson acquittal created in many minds has tended to be tempered, on this side of the Atlantic, by the thought that it could not happen here. It is true that an English jury would have returned a different verdict in this case, but it is wrong to believe that an English jury could not acquit in the face of compelling evidence.

In England, as in the US, there is no appeal against an acquittal. Jurors swear to "try the defendant and give a true verdict according to the evidence". But they cannot be challenged or impugned for returning an acquittal that is at odds with the facts.

Lord Devlin wrote that the "jury is the means by which people play a direct part in the application of the law. Constitutionally, it is an invaluable achievement that popular consent should be at the root not only of the making but also of the application of the law." Popular consent, the ordinary common sense, of the jury comes into play in various ways. When one considers a witness's veracity or the significance of circumstantial evidence, one is inevitably influenced by one's own experience. Jurors who live in a neighbourhood where late-night shopping is common are more likely to believe the accused's alibi that he was shopping late at night. Persons who have experienced police harassment are likely to interpret differently the fact that the accused ran away when approached by the police from persons who have had no such experience.

It is not irrational of jurors to be influenced not only by the police evidence but also by the police's reputation. This is because the case constructed by the police consists not only of objective facts, such as a weapon. Confessions, common in criminal cases, are the product of an interaction between the suspect and the police. An interrogator can, and often does, influence the suspect's responses. Further, police investigators shape the picture of events presented in court by decisions to pursue certain lines of inquiry but not others, to speak to some witnesses but not to others. A reputation for bias or incompetence will affect the credibility of the prosecution's case.

Juries must also exercise moral judgement. Many crimes contain general standards that give juries considerable leeway. Most offences against property, including theft, require the prosecution to prove that the accused behaved dishonestly. But the law gives no definition of dishonesty. Thus, juries actually define right and wrong.

Lastly, juries must not convict unless they are sure beyond all reasonable doubt that the accused is guilty. But as we have seen, guilt is not just a matter of fact, it is also a matter of evaluation. Jurors who believe the accused did no wrong will tend to acquit, regardless of legal definitions.

In 1985, Clive Ponting, a civil servant charged with breaching the Official Secrets Act, was acquitted because the jury felt he did the right thing when he disclosed the arrival of Cruise missiles in Britain - which shows how important it is to have our fellow citizens standing between officialdom and the criminal verdict. Their common sense not only protects us from narrow-minded application of the law, it also inspires confidence in the administration of justice.

But one can have this assurance only if the jury is composed of people like you and me. In the US, there is a deep cultural and social divide between blacks and whites. A white jury will not inspire the same confidence in a black accused or in the black community as would a black jury. So the constitution has been interpreted to give the accused a right to be tried by a jury that reflects the racial and social composition of the community. The Supreme Court explained that the exclusion of a segment of the community from the jury deprives the jury of a perspective on human events that may have unsuspected importance.

The OJ Simpson jury has brought its perspective to bear on the events. If from its point of view the police force seem biased, crude and insensitive to the black person's dignity and rights, it would throw out the case for the prosecution. Its verdict may be unfortunate in the particular case, but it has positive aspects. Its vote of no confidence in the law enforcement agencies is bound, once emotions have subsided, to lead to attempts to remedy the deficiency of trust. Even those who are not liberal- minded will come to see that correct verdicts cannot be expected unless all sections of the community feel justly treated by the system.

The writer is a Fellow of University College, Oxford.