nullum crimen sine lege

The maxim means that a person can be convicted only for an act that was an offence under a law in force when it was committed. It forbids retrospective criminal laws and requires criminal law to be clear and accessible.

Article 20(1) of the Constitution gives it effect: no person shall be convicted of any offence except for violation of a law in force at the time of the act charged. The protection applies to conviction and sentence, not to trial: a person may be tried under a new procedure or by a new court for an old offence. In international criminal law the maxim appears in the Rome Statute.

Example

A law making an act criminal from a date in the past cannot be applied to it, by nullum crimen sine lege and Article 20(1).

In Indian law

• Article 20(1), Constitution of India
• Article 22, Rome Statute of the International Criminal Court

See also

nulla poena sine lege · ex post facto · rule of law

Read more in the study notes

• White collar crime: Sutherland's concept and the Indian approach (White Collar Crimes)