How good is the judgment of jurors? It is an important question, as there are about 30,000 jury trials each year.

Substantial research on the workings of the modern British jury is difficult because, under section 8 of the Contempt of Court Act 1981, it is unlawful for jurors to disclose what went on while the jury was deliberating its verdict. But a recent study presented to the British Psychological Society's annual conference, based in simulating jury conditions, suggested that jurors are less likely to give guilty verdicts against attractive defendants. Ninety-six volunteers were given a transcript of a fictitious mugging case and a photograph of the defendant. The respondants were more reluctant to convict the attractive defendants.

There is also some evidence that people can be fooled by dishonest witnesses. In one American experiment involving 715 people, a truthful speaker was judged to be lying by 74.3 per cent of the subjects and a lying witness was judged to be truthful by 73.7 per cent.

Technically, juries are bodies of persons convened by process of law to represent the public at a trial or inquest. They must discharge their duties on oath (religious) or affirmation (secular). The word "jury" (from the Latin, jurata) denotes a "sworn body" - in other words, a group of people who have given a sworn undertaking to find the truth. Juries are used in all three main parts of the legal system: the civil process, the criminal process, and the coronial process (in coroners’ inquests).

In civil cases, in the Queen's Bench Division, there is a qualified right to a jury in cases involving fraud, defamation, false imprisonment and malicious prosecution. Under section 69 of the Supreme Court Act 1981, the right can be overridden if the trial requires a prolonged examination of documents or accounts, or any scientific or local investigation which cannot conveniently be made with a jury. In other types of civil case, the court has a discretion to order a jury trial but such orders are rarely made.

In 1957, Sir Patrick Devlin observed that the jury was a protection of democracy. He said: “The first object of any tyrant in Whitehall would be to make parliament utterly subservient to his will; and the next to overthrow or diminish trial by jury, for no tyrant could afford to leave a subject’s freedom in the hands of 12 of his countrymen.”

For the first part of its British history from the 12th century, the jury was established from people (iuratores) who were sworn to testify about their personal knowledge of the people or places in issue. Nowadays, the opposite is true, and anyone knowing anything about the case from direct experience is excluded from the panel of jurors.

The jury, however, has earlier origins. In classical Greek times the courts were very large, and in the 4th century BC would often include a great many jurors - 201 was the minimum number for a private action and 501 the minimum for a public action. Jurors voted after hearing the speeches from the claimant or prosecutor, the defendant and witnesses. Defence lawyers were not used. This arose from the desire to make the administration of justice demotic - “of the people”. In today’s miasma of regulations, though, democracy is enhanced by access to articulate advocates who know all the rules.

Over time, British jurors have done some odd things. These include making suggestions of an amorous nature to a barrister, trying to communicate via a séance with murder victims to find out who murdered them, getting drunk on vodka poured into water bottles, fighting with each other and asking the judge for the defendant’s star sign. But, on the whole, the jury is an admirable truth-finding institution.

One safeguard against the tilting of justice by beauty is the fact that High Court and crown court trials are heard by 12 jurors: enough people to overcome a swoon factor. In a standard instruction, the judge says to a jury “Each of you takes into the jury box with you your individual experience and wisdom. Your task is to pool that experience and wisdom.” The jurors’ varied ages, different sexes, and diverse backgrounds form a check against the seduction of reason by allure. The findings of the recent “attractive defendant” experiment are weakened by the fact that all 96 volunteers were students.

Speaking approvingly of the “wonderfully beautiful face” of Dorian Gray, Oscar Wilde’s character Lord Henry says “It is only shallow people who do not judge by appearances”. The law, though, takes a different view. People serving on juries must not be affected by a defendant’s looks. Undoubtedly, looks can be potent. "It was a blonde” wrote Raymond Chandler, “A blonde to make a bishop kick a hole in a stained glass window." Jurors, though, must judge the facts not the face.

Professor Gary Slapper is Director of the Centre for Law at The Open University

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