The jury is an essential part of the legal system
It must be recognise that the early function of jury is very different form what it is today. The very first jury had acted as witness and provides information to the court. Later, Henry II changed the function of jury to one who deliberates on evidence. Slowly, the jury system mold into the system we have today.  The system by which we are familiar with today, i.e. juries giving verdicts on the basis of what is related to them by witnesses at the court hearing was coming into prominence in trials of serious offences as early as the fifteenth centur The main act that governs the jury system is the Jury Act 1974, which were largely amended by the Criminal Justice Act 2003. 
A jury is a group of men and women who sit in court, listen to evidence and decide whether the court had establish beyond reasonable doubt for criminal cases or on the balance of probability for civil cases, that the defendant had commit the offence charged.
A jury is defined as a body of persons convened by process of law to represent the public at a trial or inquest and to discharge upon oath or affirmation defined public duties.  The jury's duty is to return verdicts upon issues joined in courts of civil and criminal jurisdiction or findings of fact at coroners' courts. The role of the jury is four-fold: – to weigh up the evidence and decide what the true facts of the case are, to listen to the directions of the judge as to the relevant law and then apply the law to the facts before reaching a verdict.
Juries are used in both Criminal and Civil cases although the use of juries is very small. Juries are used in the Crown Court for criminal trials of indictment, High Court - Queen’s Bench Division, County Court and in some cases the Coroners’ Courts. Less than 1% of criminal cases are decided on by a jury this is because 97% of cases are dealt by the Magistrates’ Court and from the cases that go to the Crown Court, about two out of three defendants plead guilty. Juries in criminal cases are used to decide the guilt or innocence of the defendant. Juries are used in civil cases to decide the liability and on the damages for the following cases; deformation, malicious prosecution, fraud and false imprisonment. In very exceptional cases a jury can be used in personal injury cases. In these cases a judge of character isn’t necessary so there is no need for a trail. Person injury cases should normally be tried by a judge to assess compensation award on a fixed scale. The case on Ward v James (1966) established that juries will only be used in “exceptional circumstances," the case of H v Ministry of Defence (1991) further reinforced this rule.
The use of a jury is viewed as making the legal system more open. Justice is seen to be done as members of the public are involved in a key role and the whole process is public.
There are several advantages of the system of trial by jury. Firstly, the general public acceptance of the way the jury system works. As I have already stated, the jury system has been around for many years, almost 800 years now; the fact that the jury has stood the test of time has given society a feeling of acceptance that this is the best way to decide on the outcome of indictable offences.
Secondly, the jury system gives the public a chance to participate in the legal process. Selection for jury service is basically a lottery. If the three conditions required for jury service are met; the persons name appears on the electoral register; they are aged between 18 and 70; and have lived in the U.K for at least 5 years since their 13th birthday, then there is every chance that any person could be selected for jury service. Most members of the public find this an exciting insight into the legal system; however some people find the experience extremely costly as it means that they cannot work while the trial is in progress.
A third advantage is that the jurors are totally impartial and the decision is made purely on opinion. Obviously this opinion must be heard in a majority vote of at least 10 out of 11 or 9 out of 10 jurors. The jurors vary rarely know much about the legal procedure and are therefore not case-hardened as Judges would be should they be introduced, as in alternative suggestions to the jury system.
Fourthly, the public of England and abroad have great confidence that the cases have been tried fairly and that the system is effective. With the public having great confidence in the system, it is very difficult politically to alter the system. For example, when Diplock Courts were introduced into Northern Ireland, these were greeted with displeasure as it tampered with the jury system. These courts are used in terrorist cases and are judge only courts with no jury.
A simple yet very significant reason as to why the jury system is advantageous is the fact that 12 heads are better than 1. With 12 jurors, a wide variety of opinions and input is culminated together in the final decision; a single judge has only one viewpoint and this is purely of the legal perspective.
Finally, decisions can be made on what seems right and not whether the offence is illegal or not. By this I mean that, if the defended acted in good heart and can convince the jury that his/hers action was reasonable in the circumstances, then the jury are able to acquit the defendant. A judge can only administer a verdict based on the facts laid before whereas a jury can decide based on opinion. This point has been evident in numerous recent cases such as R v Ponting (1985) - In this case official secrets were disclosed however Ponting successfully argued that the secrets were disclosed in the interest of the nation and was acquitted by the jury. A further example was R v Kronlid and Others (1996)- In this case Kronlid and others caused £1.5 million worth of damage to a fighter aircraft that was to be sold to the Indonesian Government. Kronlid successfully argued that the plane would be used to tyrannize the people of East Timor and was acquitted by the jury.
All of the above are reasons as to why the jury system is advantageous. I will now explore disadvantages of the system.
Firstly, as the selection for jury service (governed by section 1 of the Juries Act 1974 as amended by the Criminal Justice Act 1988) is totally down to chance, there is the realistic possibility that incompetent people, who are unable to deal with the court atmosphere, may be selected for jury service. This occurred in R v Chapman (1974) when a deaf juror sat through the trial without hearing a word of the trial. The Court of Appeal also decided that the juror had not prejudiced the trial and therefore the decision stood. After this case, Lord Denning caused for a suitability test to be introduced to decide on whether the juror is adequate to perform, however this could result in huge financial cost.
Secondly retrials are very expensive. The jury do not have to agree, and should they disagree, a retrial would have to be arranged. The introduction of a single judge or a panel of judges to decide would abolish this problem, as the judge would decide one way or the other. As well as retrials being expensive, the trial by jury itself costs lots more than what it would to employ a single judge to sit on the trial. This is a considerable amount and is comparatively much more expensive to the taxpayer than what a single judge would be.
Thirdly, jurors may not fully understand the trial and may be enticed to vote for the best barrister and not the best case.
A realistic problem is that jurors can be corrupted by outside influences. As jurors are not paid, only compensated for loss of earnings, then some may be tempted to accept a bribe to vote to acquit the defendant.
There is the growing feeling that certain jurors are more dominant than others and therefore dominate the jury room. Jurors can be effectively bullied into agreeing with the dominant juror.
As jurors are laymen, if the evidence points to one defendant being guilty and the other not, jurors can often be led into thinking that if one should be convicted, so should the other; in other words: guilt by association.
A seemingly obvious problem with the use of laymen in the administration of justice is that mistakes must inexorably occur. A study done over around 370 trials at Birmingham Crown Court in the late 1970’s showed three startling results: that 25% of all acquittals were questionable; that 5% of all convictions were questionable; and that there was comprehensible evidence that some trials were racially biased.
A further reason as to the disadvantages of the jury system is that some trials can be very harrowing to the jurors. This was evident in the James Bulger trial where some jurors had to receive counselling after the trial.
There are many alternatives to a jury one being that of a single judge. This method is used in civil cases and some criminal trials in N.Ireland (Diplock courts). This process is the least expensive and probably the most proficient way of running a trial. Because it eradicates public involvement there has been strong opposition to this method. However by discarding the jury they also discard any violence and intimidation to jurors and also any possible bias.
Another alternative is that of a panel of judges. This system is used in some continental countries. This method again abolishes public participation. Having a panel of judges would mean that more judges would have to be trained making it more expensive not only to get them qualified but also to pay their wages.
A judge and 2 lay assessors can also be used. This technique is used in most Scandinavian countries. This keeps some public contribution, yet loses the time and cost of using a jury: because of this, this method is thought of as the most adequate alternative. The verdict would be reached by both the judge and lay assessors. The lay assessors would be selected the same way as jurors; however the amount of public participation would dramatically decrease.
The final alternative is having a judge and a miny jury. By reducing the amount of jurors they would save some cost; conversely most of the disadvantages would still remain.
Despite all of the disadvantages with the jury system, it is still utilized today which suggests that it is an advantage to society more than it is a disadvantage.
The system of trial by jury has been successfully used in society for hundreds of years. Anything that has remained in such constant use over such a long period of time must be deemed to be worthwhile keeping. Although various alternatives have been suggested to the jury system, no one has been able to fathom a superior way to decide on the defendant’s fate. It has to be said that the system of trial by jury is used to the advantage of the public and, until any other superior alternative is introduced, it will continue to be an asset to society.