Under the English and Scottish systems of criminal justice, judges tend to see themselves (and hope to be seen by others) as quite impersonal, at least outwardly, in their administration of justice. To this end they cling to the wearing of wigs as affirmation of their anonymity.

This, despite the views of two lord chief justices separated in time by a 150 years: most recently the late Lord Taylor who had little good to say for them, and in the mid-19th century, Lord Denman who called them the silliest things in England. Taylor and Denman's view is to some degree shared by current judges, who order wigs to be removed in child abuse cases lest the sight of them give little people the giggles or, more likely, the heebie-jeebies. American judges, who share with us the same antique, accusatorial system of justice, get along pretty well without wigs, a simple black robe being considered sufficient to assert judicial authority.

There are flaws in the American criminal justice system, it is true, but I know of no one who thinks that the introduction of wigs would help to rectify them.

Yet however much English judges cherish the anonymity, and with it the impartiality they believe wigs bestow, no such impartiality is granted to the accused. In English law the accused is all that is on trial, and the only verdicts open to the jury are guilty or not guilty. Scottish criminal law, however, is different. Originally the choice of verdict in criminal cases was between proven or not proven - a judgment on the case. In time, and following English law, guilty or not guilty were introduced-judgments on the accused; but as a third choice, not proven was retained and is with us today.

Critics of the not proven verdict claim that it leaves the accused tainted, creating an unhealthy doubt in the public mind as to whether he or she committed the crime or not. This was certainly true of the famous case of Madeleine Smith, the 22-year-old daughter of a prosperous Glasgow architect who, in 1857, was charged on three counts of the murder of her lover, a Jersey clerk named Pierre L'Angelier. On the first count the verdict was not guilty, on the other two not proven. Yet this case was an exception; most not proven verdicts today are on known villains and, as with guilty verdicts, are soon forgotten.

Because of their disparate natures I have never found the guilty, not guilty, not proven verdicts to be comfortable bedfellows and, just as judges are afforded a degree of impersonality by wigs, I ask if a similar service could not be granted to the accused who, as the law never stops reminding us, are deemed to be innocent from the moment they enter the dock until the day, sometimes weeks later, when the jury return their verdict.

Why restrict not proven to the Scottish courts? Why not expand the concept to both English and Scottish courts, so that instead of the clerk of the court inquiring of the jury: "Do you find the accused guilty or not guilty?", he would ask: "Do you find the charge(s) against the accused proved or not proved?" (Disproved would be a fairer and more logical alternative, showing that the defence had succeeded, but in a country whose judicial ethos is as prosecution-minded as ours, it might be considered too much of a good thing for the Crown Prosecution Service).

Such depersonalisation of the accused has several advantages. For a start it lowers the temperature. Guilty is a highly pejorative word, inviting the response of a desire for retribution and punishment; and the tabloid press would thereby be robbed of creating, as it sometimes does, a false sense of drama - though in my view this is a carry-over from the days of hanging, when the drama was real enough. Equally the press would no longer be in a position to equate not guilty with innocence, as they sometimes do. Not guilty means no more and no less than, solely on the evidence before the court, the prosecution has failed to prove its case.

All sorts of reasons may have led to this. There may have been other evidence, which might have led to a different verdict, but which was either not introduced, or not permitted. Crown counsel may have had (like the late Mr Mervyn Griffiths-Jones) an unsympathetic or unconvincing manner. Or a brilliant defence counsel may have persuaded the jury to bring in a verdict against the weight of evidence: like the late Norman Birkett, whose client in the Brighton trunk murder case before the war was acquitted, yet who after the war admitted his guilt. What not guilty does not mean is innocent.

Even a guilty verdict, as the Birmingham Six, the Guildford Four, the Maguire Seven, Judith Ward, Margaret Livesey, Michael McMahon, Patrick Meehan, the ghosts of Walter Rowland, Timothy Evans, Derek Bentley and James Hanratty (to name, as they say, but a few) would testify, does not always mean guilty, the principal reason in the past having been corrupt policemen, desperate to secure a conviction, giving false evidence against the accused and persuading others to do the same.

Occasionally judicial crassness has also been to blame - as with Lords Bridge, Lane and Denning in the case of the Birmingham Six. I am not claiming that a proven verdict is any guarantee against a miscarriage of justice, rather that when a miscarriage has been identified, the court of appeal would no longer find itself having explicitly to admit to a wrongful conviction. It is a subtle difference morally, but I think an important one.

For a long time now I have been unhappy with our adversarial system of criminal justice, believing its very competitiveness to be an invitation to corruption, and the inquisitorial system, as practised in Germany and Holland, to be altogether fairer. I equally believe the guilty/not guilty syndrome to be an outdated, somewhat primitive hangover from other days and that proved, not proved and even disproved, are more civilised verdicts for the 21st century.

Scottish criminal law has several attractive features not evident in English criminal law: no opening speeches, which at the end of the day are apt to confuse an English jury as to what was proved and what counsel promised to prove but didn't (for example in the trial of Stephen Ward); confession evidence to be supported by other, independent evidence; and judgments on the case as well as the accused. In all of these English criminal law might well follow.

• Sir Ludovic Kennedy is a writer, broadcaster and campaigner for criminal justice