INTRODUCTION
The various arms of government exercise different powers and also play different roles in the process of enacting, administering and enforcing laws and this forms the theme of this unit. But first let us refresh our memories with an over-view of the Legal System
Judiciary; The Judiciary interprets and applies the laws through the court system. The courts of major importance in Nigeria in ascending order of authority are:

Magistrates Court/District Court
High Court
Court of Appeal
Supreme Court
SELF ASSESSMENT
Discuss the original and appellate jurisdiction of the Court of Appeal Jurisdiction; A court’s jurisdiction refers to the matters, which it has authority to hear.
Geographical; One aspect of the limits of a court’s jurisdiction is the geographical area over which the judgment of the court will have effect. Clearly the decisions of the Supreme Court of Nigeria do not have effect outside the borders of Nigeria.

Original and Appellate; Original jurisdiction refers to matters which can be commenced or originate in that court; while Appellate jurisdiction concerns cases which come on appeal to that court from another court.
Criminal and Civil; A court’s jurisdiction can also be defined by looking at its criminal and civil jurisdiction (i.e. matters arising under criminal law or not). The jurisdiction in criminal proceedings is determined by the sentence which can be imposed by the court in question. With civil proceedings, the monetary limit, i.e. the amount which can be claimed or contested, is the deciding factor.
Federal and State; Yet another description of matters which a court may hear is by reference to its State and Federal jurisdiction. This describes matters arising either under State law (e.g. prosecution in the Magistrate Court under State Road Traffic legislation) or Federal law (e.g. maintenance proceedings in the Magistrate Court exercising jurisdiction under the Matrimonial Causes Act.
Cross Vesting Legislation Found Invalid; Our federal system and the division of power between the states and the federation have caused great inconvenience at the court level. The difficulty was that often it was logical for state courts to exercise some of those federal powers and conversely for Federal Courts to exercise some powers which ordinarily fell to state courts. A good example of the problems lies in the Trade Practices field. Suppose a plaintiff wanted to sue for beach of contract and allege a failure to comply with state Sale of Goods legislation, this would ordinarily be a matter for the state High Courts. However, if the plaintiff wanted to allege a breach of the Trade Practices Act, they could not do so because that was a Federal High Court matter. Similarly, there were problems at the family law level relating to children born within wedlock. If a family comprised children born in wedlock, and also outside it, then custody would have to be determined by two separate courts.
The thrust of the scheme was to confer on the main courts in each hierarchy the general civil jurisdiction of the other courts in the scheme. That is, a State High Court may deal with a contract law issue before it and also any breaches of the Trade Practices Act 1974 (Cth) alleged as part of the claim. This was an eminently sensible scheme but see the decision of Re Wakim <http://www.austlii.edu.au/au/cases/cth/high_ct/1999/27.html>. The Constitution prevented the State Assembly from conferring state jurisdiction on the Federal Courts. The reverse that is National Assembly vesting State courts with Federal jurisdiction may be valid.

Federal Court Hierarchy; The major courts with federal jurisdiction which we shall look at are the Supreme Court, Court of Appeal and Federal High Court. There are other federal courts, such as Customary Court of Appeal and Sharia Court of Appeal.

* Jury is unknown to the modern Nigeria legal system.

The Courts
Magistrate Courts; Magistrate Courts are at the bottom of the judicial hierarchy. Magistrate Courts in the Southern States have both civil and criminal jurisdiction. A Magistrate Court hears only criminal matters in the Northern States. Civil matters are heard in the District Courts. The Magistrates are normally appointed from within the public service, usually the Justices Department, although the numbers appointed from private practice are increasing.In general terms, the criminal jurisdiction of the Magistrate Courts is limited to less serious offences, for example traffic breaches, drunkenness, common assault and so on. These come before the magistrate as simple offences. A magistrate does have a discretion to offer to the defendant that some indictable offences be tried in the Magistrate Court with the consent of the accused. However, charges of a serious nature which have to be disposed off in the High Courts are commenced in the Magistrates Court by way of committal hearing, or preliminary investigation (P). At this hearing the magistrate determines whether a case to answer has been made out against the accused person. If so, he or she is committed for trial before a Judge.

Note that some states have abolished the process of preliminary investigation. Holding charges similarly operate in some states and not in others. Civil actions where the amount involved is less than a specified sum may be determined in the Magistrate Court. In addition to its ordinary criminal and civil jurisdictions Magistrate Courts sit as Children’s Juvenile Court and Coroners Court.

The Magistrate Court also has authority under various federal statutes and state laws to exercise some jurisdiction e.g. proceedings for maintenance under the Maintenance Causes Act.
High Court; The jurisdiction of the High Court is set out in the diagram. The Court is staffed by judges appointed by the State Government normally from practicing barristers. Only one judge chairs the Court whether it is sitting in its original or appellate jurisdiction. As well as hearing court cases, judges serve on various State tribunals e.g. Armed Robbery and Fire Arms Tribunal, Election Petition Tribunals. The High Court sits at the highest level in the State court hierarchy and has unlimited jurisdiction in both criminal and civil matters. Generally, its criminal jurisdiction includes murder, attempted murder, manslaughter, serious drug offences and important serious offences such as treason and piracy. You will notice from the diagram that the High Court is presided over by one justice when exercising both original and appellate jurisdiction.

Federal High Court; The Federal High Court was established by the Federal High Court Act primarily to lighten work load of the High Court. It has only original jurisdiction including jurisdiction in industrial matters and bankruptcy.

Court of Appeal; The power of an appeal court will depend upon the legislation which gives that court jurisdiction. Ordinarily, they can allow or dismiss the appeal or refer the matter back to the lower court for a further hearing. This frequently happens in criminal cases where the appellate court decides that a person was wrongly convicted in the lower court and refers the matter back for a re-trial.

The Supreme Court; Already, we have looked at one important function of the Supreme Court in dealing with constitutional matters. In addition, it acts as an appeal court on all matters, subject to some appeal limitations. The Supreme Court is now based in the Federal Capital Tertiary (FCT).

The Privy Council
The Privy Council is really the Judicial Committee of the Privy Council and is made up of eminent English Law Lords. It sits in London, and notable jurists from countries which allow appeals in the Privy Council are sometimes invited to sit on the Privy Council. While no longer relevant to the Nigerian legal system since 1963, it still does hear appeals from some Commonwealth countries and its decisions are regarded as highly persuasive by our Courts.Other Courts and Tribunals

There are other courts or tribunals in Nigeria exercising judicial or quasi judicial functions. One example is the Rent Tribunal which deals with disputes between landlords and tenants in premises with specified rental value. This Tribunal operates in an informal manner without the necessity of legal representation (which is not possible unless there are exceptional circumstances).

SELF ASSESSMENT
Where does the Supreme Court get its power?
Has the Supreme Court any original jurisdiction? Other Components of the Nigerian Legal System
Police
It is not proposed to discuss the police in detail. Their function is well known. Suffice to say that any legal system needs an enforcement agency to carry out the decisions of courts. The police play an important part in the judicial process because they initiate almost all of the criminal cases by either warrant or summons, they prosecute cases and deal with offenders.Legal Profession
While not strictly part of our legal system, the legal profession does play an important function in its operation. You should read the textbooks on the terms used to describe lawyers, the differences between barristers and solicitors etc. In Nigeria, there is no distinction between both. Most professional people need to work with lawyers at some stage and you should know the structure of the legal profession. You should also be aware that the legal profession is continually undergoing change.

CONCLUSION
You have seen that the Legislature makes laws, the Executive enforces them while the Judiciary interprets and administers. The hierarchy of courts has also been discussed and demonstrated. You should also draw up the organogram. The Jurisdiction of each is of utmost importance since a party invariably stands to lose his/her case if he files her cause in a wrong court. You should also be familiar with the geographical, original and appellate jurisdictions of courts.

Consider some of the following issues: The appointment of judges. They are appointed from the leading barristers but is that an appropriate system? One criticism of judges is that they do not truly represent society. If the system was adopted where judges are separately trained for that office – in fact a separate career path from practicing lawyers – then perhaps some of the existing criticisms of judges would diminish. If all persons could apply to be trained as judges upon leaving the Law School (as occurs in some countries), then perhaps a wider cross section of the community and gender would be represented on the bench. Such a system might also meet the criticism that good barristers do not necessarily make good judges. The role of barristers is quite a contentious issue. Should barristers robe for court proceedings? One view is that this practice is absurd in this day; others consider that it brings some degree of solemnity and respect for the court system. Note in this context the quote from Dickens following

A final contentious matter is whether the profession should be divided between solicitors and barristers, or remain united. And I am by no means a wholesale admirer of our legal solemnities, many of which impress me as being exceedingly ludicrous. Strange as it may seem too, there is undoubtedly a degree of protection in the wig and gown – a dismissal of individual responsibility in dressing for the part – which encourages that insolent bearing and language, and that gross perversion of the office of a leader for The Truth, so frequent in our courts of law. Still, I cannot help doubting whether America, in her desire to shake off the absurdities and abuses of the old system, may not have gone too far into the opposite extreme; and whether it is not desirable, especially in the small community of a city like this, where each man knows the other, to surround the administration of justice with some artificial barriers against the ‘Hail fellow, well met’ deportment of everyday life. (Source: Dickens

SUMMARY
In this Unit, you have learnt about the judiciary, its jurisdiction and personnel. You also differentiated between federal and state Courts and other components of the Legal System. In the next Unit, we shall discuss the related issues of Separation of Powers and the Rule of Law.

source: https://projectandmaterials.com/emrisolution/2015/04/21/the-nigerian-legal-system-administration-and-enforcement-of-law-the-nigerian-legal-system-overview/

Assessing the Challenges of Area Court’s Jurisdiction on the Administration of Justice:  A Case Study of the Federal Capital Territory, Abuja

Area Court plays great and important role in the administration of justice in Northern parts of the country, and more particularly the Federal Capital Territory as it hears both criminal and civil cases to the extent set forth in the warrant establishing it. However, it is confronted and bedeviled by so many constraints and challenges in trial of both civil and criminal proceedings arising...

http://www.scharticles.com/assessing-the-challenges-of-area-court-jurisdiction-on-the-administration-of-justice/