retrospective operation

Laws are presumed to be prospective. A statute affecting substantive rights or creating new liabilities does not operate retrospectively unless the legislature says so expressly or by necessary implication. Procedural laws, by contrast, are presumed to apply to pending proceedings, since no one has a vested right in a particular procedure, unless doing so would affect accrued rights. Declaratory and clarificatory laws are usually retrospective.

Parliament and State legislatures may make laws retrospectively, including tax laws and validating Acts, subject to the Constitution. But Article 20(1) forbids retrospective criminal laws: no one can be convicted for an act that was not an offence when done, or given a heavier penalty than the law then provided. It does not stop a retrospective reduction of punishment in the accused's favour.

Example

Article 20(1) barred applying the new, higher minimum sentence to an offence committed before the amendment.

In Indian law

• Article 20(1), Constitution of India
• Section 6, General Clauses Act, 1897

See also

ex post facto · repeal · nullum crimen sine lege · prospective overruling

Read more in the study notes

• Control of delegated legislation: parliamentary, procedural and judicial (Administrative Law)
• Article 13: pre- and post-constitutional laws, severability, eclipse and waiver (Constitutional Law I)
• Joint Hindu family and coparcenary (Family Law I - Hindu Law)
• The Hindu Succession (Amendment) Act, 2005 (Family Law I - Hindu Law)
• Wakf and the mutawalli (Family Law II - Mohammedan Law)
• Human rights: meaning, nature and kinds (Human Rights Law and Practice)