In general, the principle of legality is a universal principle. This is a standard of compliance within the meaning of the criminal law. The principle of legality is the yardstick by which laws are measured to determine whether they are compatible with universal criminal law. This is a necessity for the civilized world in the procedural system of criminal law. The third principle is the presumption of innocence. This is a very well-established principle in both the law of evidence and procedural law. It contains the provision of article 36, paragraph 5, of the Constitution, which provides that any person charged with a criminal offence in a criminal case shall be presumed innocent until proven guilty. Similarly, the public outcry over the arrest of people violates the principle of legality and must also be avoided. This means that only the law can define a crime and prescribe a penalty (nullum crimen, nulla poena sine lege, which means no crime without penalty). It also states that criminal law cannot be interpreted broadly to the detriment of an accused, for example by analogy. According to this principle, a criminal offence must be clearly defined in the law.
The legal concept includes both written and unwritten law and implies qualitative requirements, particularly in terms of accessibility and predictability. The conditions are met if individuals can now determine from the wording of the relevant provision and, where appropriate, by means of judicial interpretation, which acts and omissions render them criminally liable. The principle of legality also includes the provision prohibiting the retroactive application of criminal law to the detriment of the accused. This principle is enshrined in the constitutions of many countries as well as in the most important international convention for the protection of human rights. Another important principle is the power of an appellate court to overturn the conviction of a lower court if it finds that there has been an error of justice. This principle is firmly rooted in the doctrine of judicial primacy (stare decisis), according to which decisions of higher courts are binding on lower courts. For example, section 240 of the Constitution provides that the Court of Appeal has the right to hear appeals to the High Court and other courts competing with the High Court. The principle of legality stipulates that a person cannot be charged with a criminal offence if it does not constitute a criminal offence at the time the offence was committed. In addition, no heavier penalty may be imposed on the person if it was imposed after the commission of the offence. The right to bail is not automatic and is therefore not granted ex officio. While it is common knowledge that bail can be granted for almost any legally known crime, certain conditions must be met before a person is granted bail. The Act provides only the substantive principles and procedure to be followed when granting bail in court and by the police, ignoring the various preconditions to be taken into account before bail is granted.
The law expressly leaves these conditions to the discretion of the judge or magistrate concerned. Some of the conditions that the court has applied over the years to grant and/or reject a bail application are: Under these principles, professional organizations have been held criminally liable. In DPP v. Kent & Sussex contractor. A company was sued for fraudulent use of a document. In R V. ICR College Ltd, a company, was convicted of conspiracy to commit fraud, an offence that requires mens rea to be an integral part of the second fundamental principle is that criminal laws should not apply retroactively. This means that laws should not go back in time to hold people accountable for actions taken before the law was introduced. This principle is enshrined in article 36, paragraph 8, of the 1999 Constitution.
In the Nigerian context, the military has not respected the principle of legality in Nigeria by enacting retroactive laws. Therefore, the assessment of the principle of legality in a military regime is void. In the civil system, however, people believe in due process and the principle of legality works better. Although in use, there have been issues with the app in force, especially in Nigeria. However, in order for the principle of legality to be better respected, legislators must pass laws that are respected, not retroactive laws. The attitude of jungle justice is also not helpful to the principle of legality in Nigeria and should therefore be avoided altogether.