A Guide to Protection in Respect of Conviction for Offences in India

Jurisdiction and scope: India; litigation under Article 20 of the Constitution. This note covers the three constitutional protections and an initial record-review checklist. It does not replace offence-specific statutory defences or determine whether a particular regulatory proceeding is criminal prosecution.

Law checked: 7 October 2026. Next review: 7 April 2027.

Short answer

Article 20 contains three distinct rules. Clause (1) bars conviction for conduct that was not an offence when committed and bars a greater penalty than the law then permitted. Clause (2) prevents a person from being prosecuted and punished more than once for the same offence. Clause (3) prevents a person accused of an offence from being compelled to give testimonial evidence against himself or herself. Do not merge these tests.

1. Ex post facto criminal liability

For Article 20(1), identify the date of conduct, the offence then in force and the maximum penalty then available. The clause protects against retrospective creation or aggravation of criminal liability. It does not give a fundamental right to the criminal procedure, forum or evidentiary regime that existed on the offence date. A later beneficial sentencing provision may require separate statutory and precedent analysis; do not assume every later reduction applies retrospectively.

2. Double jeopardy

The constitutional words are “prosecuted and punished for the same offence.” Both elements matter. The comparison is offence-specific, not merely fact-specific: overlapping facts do not themselves establish that two offences have identical legal ingredients. An earlier departmental, customs or other administrative adjudication is not automatically a prosecution before a court or judicial tribunal for Article 20(2). Separately test section 337 BNSS, issue estoppel and any special-statute bar; they are not interchangeable with Article 20(2).

3. Compelled self-incrimination

Article 20(3) can operate during investigation as well as trial. Record three questions: was the person an accused when the material was compelled; was there compulsion; and was the material testimonial—that is, a compelled communication of personal knowledge tending to incriminate? The protection does not ordinarily treat fingerprints, specimen signatures or handwriting, voice samples and comparable physical characteristics as testimonial communication. Compulsory narco-analysis, polygraph or BEAP testing presents a different constitutional problem because it seeks personal knowledge through compelled responses.

For police questioning under the current code, section 180(2) BNSS preserves the right not to answer a question whose answer would tend to expose the person to a criminal charge, penalty or forfeiture. In a saved CrPC investigation, the corresponding provision is section 161(2). Determine the governing code under section 531 BNSS rather than citing both indiscriminately.

Practical review steps

1. Freeze the chronology: conduct date, amendment date, commencement date, first prosecution, result and proposed later proceeding.
2. Compare legal ingredients: prepare a side-by-side element table for the earlier and later offences.
3. Classify the first forum: identify whether it exercised criminal judicial power or administrative/regulatory power.
4. Identify the compelled act: distinguish oral or written communication of knowledge from physical identifying material.
5. Preserve the compulsion record: summons, questionnaire, custody record, order directing the sample or test, objection and response.
6. Plead the correct protection: Article 20(1), (2) and (3) require different facts and relief. Add statutory protections separately.

Common errors

• Equating “same facts” with “same offence.”
• Treating every regulatory penalty as prior prosecution and punishment.
• Limiting Article 20(3) to testimony in court.
• Assuming all compelled physical samples are testimonial evidence.
• Citing CrPC section 161(2) without checking BNSS sections 180(2) and 531.

Official sources

Automated-research disclosure: This correction was prepared from the linked constitutional, statutory and Supreme Court texts through automated research and independently rechecked against each stated test.