Principle of Legality

principle of legality

The principle of legality in criminal law declares that no crime and punishment can exist without a legal base. It is also known as nullum crimen, nulla poena sine lege.  It is Latin for no crime, no punishment without law. A person shall not be convicted or punished for an act which is not in violation of existing law or which is not criminalised by law at the time it was committed. During criminal procedures, this principle of legality keeps the supremacy of law and ensures fair and transparent judgement.

The Principle of legality is closely associated with the principle of non- retroactivity and the principle of specificity. The former states that a person cannot be prosecuted by a law that is passed retroactively to criminalize the action which was not criminal at the time of being committed. The latter demands a sufficiently precise definition for the proscribed act. A person cannot be convicted by law for a crime that is not publicly declared or defined as a crime. But, ignorance of the law is not a legitimate defense.

The principle of legality also ensures the prohibition of analogy. It requires a strictly construed definition of the crime. An unclear law does not form the basis to prosecute anyone. The principle of legality is a fundamental human right. It protects people from unjust, biased and arbitrary judgments.

Origin, Conception and Interpretation

Anselm Von Feuerbach formulated the famous maxim ‘Nullum crimen, nulla poena sine lege’ in 1813.  It was also the part of penal code of Bavaria. The principle is stated in various declarations of Human Rights from 1789 till present. There are various examples in international law where the principle was ignored or (at the very least) eluded.

During Nuremberg trials[1] of the late 1940s, judges from major allied powers: America, Britain, France and the Soviet Union conducted 13 trials from 1945-1947. These trials indicted 177 Germans and Austrians. Out of which 35 pronounced guilty, 25 executed, 20 sentenced to life imprisonment and 97 sentenced to shorter prison terms. These trials also convicted low ranking soldiers. Whereas, before World War II, the prosecution was subjected to high ranking commanders or head of state only. In the trials, the prosecution of Nazis pleaded the defense of superior, which was an accepted principle of the criminal law. At the trials, the prosecution was denied protection from this retroactive criminal law on the grounds that their act was against humanity.

Nuremberg trial served as a model for of the Universal Declaration of Human Rights (UDHR), 1948and Geneva Convention III, 1949.[2]

The Article 11(2) of the Universal Declaration of Human Rights (UDHR)[3], 1948 structured the definition of the principle which states:

  • ‘No one shall be held guilty of any penal offence on account of any act or omission which did not constitute a penal offence, under national or international law, at the time when it was committed. Nor shall a heavier penalty be imposed than the one that was applicable at the time the penal offence was committed.’

The Geneva Convention III, 1949focused on the Treatment of Prisoners of War. The convention with the help of an impartial humanitarian body, the International Committee of the Red Cross (ICRC), conducted a study and catalogued 161 customary international humanitarian laws (IHL) and protocols[4]. Rule 101 is the principle of legality which states:

  • ‘No one may be accused or convicted of a criminal offence on account of any act or omission which did not constitute a criminal offence under national or international law at the time it was committed; nor may a heavier penalty be imposed than that which was applicable at the time the criminal offence was committed.’

The General Assembly of the United Nations on 19 December 1966 adopted International Covenant on Civil and Political Rights (ICCPR)[5].Its article 15 defines the principle similar to UDHR which states:

  • No one shall be held guilty of any criminal offence on account of any act or omission which did not constitute a criminal offence, under national or international law, at the time when it was committed. Nor shall a heavier penalty be imposed than the one that was applicable at the time when the criminal offence was committed. If subsequent to the commission of the offence, provision is made by law for the imposition of a lighter penalty, the offender shall benefit thereby.
  • Nothing in this article shall prejudice the trial and punishment of any person for any act or omission which, at the time when it was committed, was criminal according to the general principles of law recognized by the community of nations.

Principle of Legality in India

The constitution of India has adopted the principle nullum crimen, nullum poena sine lege; i.e., the principle of legality. In the constitution of India, part 3 of fundamental rights under the rights of freedom, article 20 (1) states, ‘No person shall be convicted of any offence except for violation of a law in force at the time of the commission of the Act charged as an offence, nor be subjected to a penalty greater than that which might have been inflicted under the law in force at the time of the commission of the offence.’[6]

Article 20(1) of the Indian constitution can be understood in two parts:

  • The first part implies that a person is only convicted of violating a law which was in force when the act charged was being committed. A law enacted after, an act done earlier (not an offence when done) as an offence, will not make the person liable for being convicted under it. For example, ‘The Dowry Prohibition Act, 1961 came into force from 20.5.1961. A person guilty of accepting dowry is punishable under the Act after 20.5.1961 and not before 20.5.1961.’
  • The second part immunes a person from a penalty more than what he might have incited at the time of his committing the crime. Meaning that an ex-post-facto law or retroactive law, cannot make a person suffer more than what he was subjected to at the time of committing the offence. For example, Satwant Singh vs Punjab[7]. Satwant Singh was charged according to section 420 of Indian Penal Code (IPC). According to Sec. 420 IPC, an unlimited fine can be imposed for offence punishable under this provision. Later, an ordinance laid down the minimum fine which a court must inflict on a person convicted u/s 420 IPC. The Supreme Court held that article 20(1) was not infringed by the ordinance because the minimum penalty fixed by it could not be said to be greater than what could be inflicted.

The definition in section 3 (37) of the general clauses act is applied as there is no definition of offence in the constitution and for application of article 20(1) there has to be an ‘offence.’

Case Study: Rattan Lal vs State of Punjab[8]

Rattan Lal, age 16 years was found guilty of an offence and was awarded a rigorous imprisonment of 6 months with a fine on 31-5- 1962. His appeal was dismissed by the session’s judge on 22-9-1962 and by the high court on 27-9-1962. The probation of offenders act came into force on 1-9-1962. No plea was taken before the high court that the boy should be given benefit of the act. Later he filed an appeal in the Supreme Court by special leave and it was argued whether he should be given the benefit of the act or not. Respondent argued that the act is not retrospective and the offence was committed much before the act came into the force. But the Supreme Court observed that a retroactive law which only pacifies the rigorous of a criminal act does not fall within the said prohibition. The court therefore ruled in favour of Rattan Lal to reduce the punishment of the young offender.


The Principle of Legality or Article 20(1) of the Indian Constitution provides protection with respect to the conviction of an offence. It safeguards civilians from arbitrary bias. It upholds the sanctity of law guaranteeing the fundamental rights of people. But, it should be ensured that people do not misuse their right. Therefore, the sovereign legislature has the power to enact prospective as well as retrospective laws, as it is provided in article 245 of the Indian constitution[9].


1. A asked for dowry from B at the time when there was no law against it. After the enactment of Dowry Prohibition Act, 1961 passed A cannot be punished for taking dowry as it happened before the act was enacted.

2. P, a minor committed a crime before the enactment of Probation of Offenders Act but made an appeal to the SC to avail its facilities. Under the Principle it was declared that the law cannot punish retroactively but can decrease the punishment, if such a situation arises.

Frequently asked questions

1. What does the principle of legality mean?

It means that a punishment can only be awarded on legal grounds. In essence, a person cannot be punished for an act which is not an offence or legally defined as crime at the time when the act was being committed.

2. Why is it required in criminal law?

It is required so as to prevent the state from punishing an accused out of arbitrary bias.

It prevents the state from charging the accused retroactively and prohibits it from employing new laws only to justify the acts of the accused as criminal.

3. Does it help in just and fair jurisdiction?

Legally it does. As it mostly ends up in favour of the defendant. But, depending upon case to case it challenges the morality of the judgement. For example, an accused of rape was charged with only indecent assault because at the time when the act was committed, the definition of rape was limited to only vaginal penetration anal penetration was not included[10]. In such cases the judgement is not fair to the victim of the said crime.

Edited by Parul Soni
Approved & Published – Sakshi Raje


[1]Criminal Law Journal, vol. 13, no. 4, August 1989, pp. 251–62, ISSN 0314-1160.The right to protection from retroactive criminal law by James Popple.



[4]ICRC, Customary IHL Database 12-04-19.



[7]1960 AIR 266, 1960 SCR (2) 89.

[8]Rattan Lal Vs state of Punjab, AIR 1965 SC 444.


[10] Masiya v Director of Public Prosecutions and Others 2007 (5) SA 30 (CC).

Rajni Negi
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