Protection against Ex-post facto law
Article 20(1): no conviction under a later law and no heavier penalty than the law in force when the act was done
Scope: Article 20(1) only; the protection against double jeopardy (Article 20(2)) and against self-incrimination (Article 20(3)) have their own notes.
In one minute
Article 20(1) stops the State from punishing a person under a law that came after the act. It also stops a heavier punishment than the law allowed when the act was done.
Exams ask for the two limbs, the fact that it covers criminal law only, and the rule that a milder retrospective law is allowed. Every person gets this protection, not only citizens.
Exam focus
- Frequency: Rarely asked
- Usually asked as: Long answer (10 to 15 marks)
Legal provision
- Article 20(1): 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 shall a person 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.
- Article 359(1): during a Proclamation of Emergency, the President may suspend the right to move a court for Part III rights, except those in Articles 20 and 21. So this protection survives an emergency.
Meaning and definition
An ex post facto law is a law made after an act that changes the legal result of that act. Article 20(1) bars such a law only in one field: criminal liability and punishment. It rests on two ideas: nullum crimen sine lege (no crime without a law) and nulla poena sine lege (no punishment without a law).
- 1. Is the proceeding about a criminal offence and its penalty?No: Article 20(1) does not apply.
- 2. Was the act an offence under a law in force when it was done?No: the conviction is barred.
- 3. Is the penalty greater than the law in force then allowed?Yes: the extra penalty is barred.
- 4. ResultThe conviction and the penalty stand.
Detailed explanation
Step 1: the first limb, conviction
A person cannot be convicted for an act that was not an offence under any law when it was done. The test is the law in force at the time of the act, not the date of trial.
Example. On 1 March, Ravi flies a drone near a stadium. No law forbids it. On 1 April, Parliament makes it an offence. Ravi cannot be convicted for the flight on 1 March.
Step 2: the second limb, penalty
Even if the act was already an offence, the sentence cannot be heavier than the then law allowed. A new law that raises a fine to imprisonment cannot be applied to an earlier act.
Example. In 2020 the penalty for an offence was a fine of Rs. 1,000. In 2023 the law adds three months of imprisonment. A person who did the act in 2020 can only be fined.
Step 3: what the Article does not cover
The words are "convicted" and "penalty". The Article bars retrospective criminal liability and punishment. It does not stop a law from taxing or imposing a civil liability retrospectively. Preventive detention is not a punishment for a past offence, and Article 22 governs it.
Changes in the Code itself show the rule in daily use. Offences committed before the Bharatiya Nyaya Sanhita, 2023 came into force on 1 July 2024 are dealt with under the earlier law.
Don't confuse: harsher and milder retrospective laws
| Point | Harsher law | Milder law |
|---|---|---|
| Effect on the accused | Creates a new offence or raises the penalty | Removes the offence or reduces the penalty |
| Article 20(1) | Bars it for earlier acts | Does not bar it |
Inside Article 20(1). A new law makes an old act an offence and the State prosecutes it. The conviction is barred.
Just outside it. A new law lets a first-time offender go on probation instead of prison. The accused may use it, because it only helps him.
Common mistakes
- Saying Article 20(1) bars all retrospective laws. It bars only retrospective criminal liability and heavier penalties.
- Saying it protects only citizens. It protects every person.
- Saying the Article stops a milder retrospective law. The Court applied a milder law in Rattan Lal.
- Using the date of trial. The law in force on the date of the act decides.
Apply it
Problem
On 10 January, Meena sells a product that no law prohibits. On 1 February, a new Act bans the product and punishes sale with two years' imprisonment. The State prosecutes Meena for the sale on 10 January. Is her conviction valid?
Issue. Can Meena be convicted under the new Act for an earlier sale?
Rule. Article 20(1) bars conviction except for violation of a law in force when the act was done.
Application. The sale was not an offence on 10 January. The new Act came later.
Conclusion. The conviction is barred. Sales after 1 February can be punished.
Leading case laws
- Rattan Lal v. State of Punjab (1965)
Facts. An accused was convicted before the Probation of Offenders Act, 1958 came into force. The appeal was pending when it did.
Principle. The Court applied the Act to him. A law that only helps the accused is not hit by Article 20(1).
Why it matters. It marks the line between harsher and milder retrospective laws.
How to write this answer in the exam
5-mark answer
- Quote Article 20(1) in two limbs.
- Explain ex post facto law.
- Note that it covers criminal law only.
- Give the Rattan Lal rule.
10-mark answer
- Article 20 in outline, with the three protections.
- Limb one: conviction, with an example.
- Limb two: penalty, with an example.
- Limits: civil and tax laws, preventive detention.
- Rattan Lal and milder laws.
- Conclusion: protection survives an emergency (Article 359).
Key points to remember
- Article 20(1) has two limbs: conviction and penalty.
- The law in force on the date of the act decides.
- It covers criminal law only.
- A milder retrospective law is allowed (Rattan Lal, 1965).
- Every person is covered. It cannot be suspended in an emergency (Article 359(1)).
Quick self-test
1. What are the two limbs of Article 20(1)?
No conviction except for violating a law in force at the time of the act, and no penalty greater than that law allowed.
2. Does Article 20(1) stop a retrospective tax law?
No. It covers only criminal liability and penalty.
3. Can the accused use a milder law passed after the act?
Yes. Article 20(1) does not bar a law that only helps him (Rattan Lal).