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Art. 20 of the Constitution of India provides safeguards against conviction, arrest, and detention. This right is available to both citizens as well as non-citizens, including a corporation. It cannot be suspended even during an emergency by an order under Art. 359.

When the draft for this article was being prepared, Mr. B.N. Rau (Constitutional Advisor) pointed out that most progressive countries were having three Constitutional Rights, viz, Ex-Post Facto Laws, Double Jeopardy, and Self-Incrimination; the three clauses given under this Article.

Art. 20(1): Protection form Ex-Post Facto Laws

This clause 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.”

It simply means that if an individual commits an offence at the present day, he/she shall be governed by the present days’ laws; any change in the said laws in future shall not have affect the concerned individual. In short, a new law cannot punish an old act. An act which is not an offence on the date of its commission (as per the actual factual law existing on that date) cannot be made an offence on a subsequent date.

Art. 20(1) is not applicable to a trial or a civil liability or preventive detention case or disciplinary proceedings. An ex-post facto law is a law which is enacted subsequent to some occurrence i.e. the commission of some act or omission. In other words, it declares some act or omission as an offence for the first time after the completion of the offence. Such a law may also enhance the punishment/penalty for an offence subsequent to the commission of that offence Further, it may prescribe a new and different procedure for the prosecution of an offence subsequent to the commission of that offence. Art. 20(1) does not cover the last category of ex-post facto laws

Important Case Laws

  1. Kedarnath v. State of West Bengal (1953) – This case highlighted the constitutionality of Special Courts under Article 14 and protection against ex-post facto laws under Article 20(1).

The Special Court had sentenced Bajoria to a fine of ₹50,000 under a section of the West Bengal Criminal Law Amendment (Special Courts) Act, 1949, that mandated a fine equal to the financial gain obtained through the crime. The Supreme Court observed that when the offense was actually committed (between 1943 and 1947), the Indian Penal Code did not contain any provision for this mandatory compensatory fine. The Bench ruled that the state cannot retrospectively increase or enhance a criminal penalty beyond what was legally permissible at the time the offense occurred. As a result, the Court struck down the enhanced financial penalty.

  1. State of West Bengal v. S.K. Ghosh (1962) – In this case, it was held that the forfeiture of stolen or embezzled public funds is a civil compensatory recovery tool, not a criminal “penalty”, and therefore does not violate the protection against ex-post facto laws under Article 20(1).

The Bench ruled that the mere use of the word “forfeiture” does not make a statutory provision a criminal punishment. While IPC-based forfeiture takes away lawfully owned private assets as a punishment, forfeiture under Section 13(3) of the Criminal Law (Amendment) Ordinance, 1944, is a speedier administrative method to recover state funds that the criminal had embezzled. It is a civil remedy equivalent to a restitution suit and falls entirely outside the scope of Article 20(1).

  1. Rattan Lal v. State of Punjab (1965) – In this case, the Supreme Court established the “Rule of Beneficial Interpretation” under Article 20(1) of the Indian Constitution, ruling that retrospective criminal laws are completely valid if they reduce penalties or benefit the accused.

Article 20(1) states that a person cannot be convicted under a law that didn't exist when the act occurred, nor face a penalty greater than what was active at the time. The Supreme Court clarified that this constitutional bar only applies to retrospective laws that create new offenses or enhance punishments. It does not bar retrospective laws that mitigate, lessen, or remove a criminal penalty. The Court ruled that an accused person is entirely entitled to the benefits of any subsequent legislative amendment that reduces a sentence, lowers a fine, or provides a reformative alternative to jail time.

  1. Soni Devrajbhai Babubhai v State of Gujarat (1991) – In this case, the Supreme Court clarified that Section 304B of the Indian Penal Code (IPC), which defines and penalises “dowry death”, is a substantive criminal offence that applies purely prospectively and cannot be used retroactively due to the constitutional bar under Article 20(1).

The Supreme Court ruled that Section 304B created a completely distinct, new substantive offence that did not exist in the criminal statutes prior to November 19, 1986. Under Article 20(1) of the Indian Constitution, an individual cannot be convicted or penalized for an act under a criminal law that was not in force at the exact time the act was committed.

  1. Mohan Lal v. State of Rajasthan (2015) – In this case, the court analysed the legal definition of “possession” under the Narcotic Drugs and Psychotropic Substances (NDPS) Act, 1985, ruling that a criminal offense can still be prosecuted under a new Act if the unlawful possession continues across the date the law changes. The Supreme Court held that possession is not a single, isolated event but a continuous status over time.

When Art. 20(1) does not apply?

  1. No prohibition for change in procedural laws - A person does not have the fundamental right to be tried by a particular procedure. Art. 20(1) does not prohibit the 'trial' of offences under the ex-post facto laws. A law which retrospectively changes the venue of a trial or an amended law which provides for setting up of a Special Tribunal to try summarily the offences under the Act in question have been upheld by the court as not violating the Art.20(1). [Transmission Corpn., A.P. v Ch. Prabhakar AIR 2004 SC 3368].
  2. Benefit of reduction in punishment - Art. 20(1) does not bar the accused from taking benefit of the reduction in punishment (i.e. modifications of the rigour of criminal law). The rule of beneficial construction required that an ex-post facto law could be applied to reduce the punishment. If any subsequent legislation tones down punishment for an offence, legislative benevolence can be extended to the accused who awaits judicial verdict regarding sentence.
  3. No application to civil laws - There is no limitation on retrospective operation of civil laws including tax laws or disciplinary proceedings. Non-fulfilment of civil liability may entail penal damages or imprisonment. But, that does not make out a case under Art. 20(1). Thus, where the non-payment of compensation by the employers closing their undertaking was made punishable (via imprisonment) retrospectively by the Act, the Apex Court upholding the constitutionality of the impugned Act held that the liability imposed was civil liability and since the failure to discharge a civil liability was not an offence, Art. 20(1) would have no application. [Hatisingh Mfg. Co. v UOI AIR 1960 SC 923].

Art. 20(2): Protection from Double Jeopardy

It states, “No person shall be prosecuted and punished for the same offence more than once.” It is based on the Latin maxim, “Nemo Debet Bis Vexari”, which simply means that an individual should not be punished twice for the same offence. The principle of double jeopardy has been already recognized in the Sec. 26, General Clauses Act and Sec. 337, BNSS (earlier S.300 CrPC). The object is to avoid the harassment, which may be caused to a person for successive criminal proceedings where only one crime has been committed by him.

Double jeopardy has two aspects:

  1. Autrefois Convict – The plea of autrefois convict avers that the defendant has been previously convicted in respect of the same offence; and
  2. Autrefois acquit – It is the plea that the accused has been acquitted on a charge for the same offence for which he is being prosecuted.

The Constitution of India protects a person from being prosecuted and convicted more than once for the same offence. Both prosecution and punishment must co-exist for the operation of Art. 20(2). Where a person having been prosecuted is acquitted, he can be prosecuted for the same offence again. In other words, Art. 20(2) contains the principle of autrefois convict only and does not include autrefois acquit. Protection against autrefois acquit is to be found in Sec. 337, BNSS (earlier S.300 CrPC). It is a statutory right; not a fundamental right. Art. 20(2) would have no application to a continuing offence viz. pollution activities (nuisance), continued unauthorized possession of land, violation of copyright, etc.

Important Case Laws

  1. Maqbool Hussain v. State of Bombay (1953) – In this case, it was held that the protection afforded by Art. 20(2) is attracted only in respect of punishment inflicted by court of law or judicial tribunal. Administrative and Departmental proceedings don’t come under the purview of Art. 20(2).

Article 20(2) states that “no person shall be prosecuted and punished for the same offence more than once.” The Supreme Court clarified that the words “prosecution” and “punishment” are not generic terms. To trigger this constitutional protection, the first proceeding must have taken place before a court of law or a judicial tribunal, and the individual must have been tried under standard judicial procedures.

  1. Thomas Dana v. State of Punjab (1958) – In this case, the Supreme Court reinforced the rule set in Maqbool Hussain, deciding that hefty personal monetary penalties imposed by administrative bodies do not trigger double jeopardy protections under Article 20(2).

The majority bench ruled that to successfully claim protection under Article 20(2), a person must concurrently satisfy three conditions:

  1. There must be a prior prosecution.
  2. There must be a prior punishment.
  3. Both must have taken place before a court of law or a judicial tribunal.

[Note: Justice K. Subba Rao delivered a famous lone dissent in this case, arguing that the massive personal penalty of ₹25 lakhs essentially functioned as a heavy punitive sentence, and exposing them to subsequent prison terms directly violated the spirit of human rights protections under Article 20(2)].

  1. Leo Roy Frey v Superintendent, District Jail (1958) – In this case, it was held that a criminal conspiracy is a completely separate offence from the actual crime committed, meaning an individual can be tried for both without violating the Constitution.

The case is the direct procedural precursor to the highly cited Thomas Dana ruling. The Court ruled that the offence of criminal conspiracy to commit a crime is entirely distinct from the substantive crime that forms the object of that conspiracy. A conspiracy begins and is legally complete the moment the unlawful agreement is formed, well before the actual crime is attempted or completed. Conversely, the physical crime of smuggling does not require a conspiracy element to be proven as a necessary legal ingredient. Because the two offences are structurally separate, prosecuting an individual for both does not violate the “same offence” requirement of Article 20(2).

Art. 20(3): Protection against Self-Incrimination

Clause 3 states, “No person accused of any offence shall be compelled to be a witness against himself.” It ensures the right to remain silent. This provision governs both spoken testimonies and written records in criminal cases, but it excludes physical inspections or body searches. It is based on the maxim, “Nemo Tenetur Seipsum Accusare”, which means, “no one is bound to accuse themselves”.

To avail protection under Art. 20(3), three essential ingredients need to be fulfilled:

  1. One must be charged for an offence;
  2. You are asked to be a witness against the said offence; and
  3. The evidence you are asked for will be used against yourself.

Protection against criminal proceedings only - The protection is confined to criminal proceedings before a court of law or a judicial tribunal. It does not extend to civil proceedings or such proceeding which are not of a criminal nature e.g. under the Customs Act or the Foreign Exchange Regulation Act. In these proceedings, a person cannot refuse to answer on the ground that it might incriminate him.

Important Case Laws

  1. Kalawati v State of Himachal Pradesh (1953) – In this case, the court held that a confession made by an accused does not violate the protection against self-incrimination under Article 20(3) if it is made voluntarily without any external threat, promise, or coercion.

The Supreme Court held that Article 20(3) protects an accused individual from being compelled or forced to give evidence against themselves. It does not act as a complete bar against voluntary disclosures. If an accused chooses to make a confession before a magistrate under Section 164 of the CrPC out of their own free will, without any threats or promises, the constitutional protection against self-incrimination is not triggered. The Court ruled that simply retracting a confession at a later stage of the trial does not automatically make the original statement illegal or unconstitutional. A retracted confession can still be used as valid legal evidence to convict an accused, provided the court finds it was originally made voluntarily and its contents are substantially backed up (corroborated) by other independent evidence or facts found during the investigation. The judgment established that for Article 20(3) to apply, there must be active subjection to structural coercion or third-degree methods by state authorities to force an admission.

  1. M.P. Sharma v. Satish Chandra (1954) – It is a landmark case that first defined the scope of the right against self-incrimination under Article 20(3) of the Indian Constitution, specifically ruling that search and seizure operations do not violate this right.

The Court looked deeply at the words “to be a witness” in Article 20(3). It ruled that this protection is not strictly limited to oral testimony given inside a courtroom witness box. The fundamental right extends to any form of communication, including producing private documents, fingerprints, signature samples, or written notes, if forced out of an accused person during police interrogation or judicial investigations.

  1. State of Bombay v. Kathi Kalu Oghad (1961) – In this case, the court refined the right against self-incrimination under Article 20(3) by drawing a sharp distinction between “physical evidence” (which is legal to collect) and “testimonial evidence” (which cannot be forced).

This case modified the M.P. Sharma precedent. The majority bench ruled that the phrase “to be a witness” under Article 20(3) does not mean providing mere physical identification or mechanical markers. To act as a witness, an accused person must communicate personal knowledge of the crime through oral speech or written statements. Giving a fingerprint, a signature sample, a foot impression, or a handwriting specimen does not convey personal knowledge; it merely exposes an unchanging physical characteristic for laboratory comparison. Therefore, collecting these markers does not violate the Constitution. The Court clarified that Article 20(3) only bars compelled testimonial evidence. For the constitutional protection to apply, two conditions must be met:

  1. The individual must be formally accused of an offence at the time the statement is extracted.
  2. The individual must be subjected to structural coercion, threats, or physical force to speak or write out an admission of guilt.

[Note: Decades later, the landmark three-judge bench in Selvi v. State of Karnataka (2010) heavily relied on this distinction. It ruled that involuntary Narco-Analysis and Polygraph tests violate Article 20(3) because they forcefully extract mental knowledge and thoughts, whereas collecting DNA, blood samples, or fingerprints remains perfectly valid under the Kathi Kalu Oghad framework.]

  1. Nandini Satpathy v. P.L. Dani (1978) – In this case, the court massively expanded the right against self-incrimination under Article 20(3) and Section 161(2) of the CrPC, establishing that an accused has a “right to remain silent” during police interrogations.

The Bench ruled that the protection against self-incrimination kicks in the very moment a suspect is questioned by the police, long before any formal chargesheet is filed. The Court clarified that an accused cannot be forced to answer any question if the response has the potential to expose them to a criminal charge, a penalty, or forfeiture. This protection covers not just direct confessions of guilt, but any answer that could act as a link in the chain of evidence needed to convict them. Expanding on the concept of “compulsion,” Justice Krishna Iyer noted that coercion is not limited to physical torture or third-degree methods. Severe mental pressure, prolonged isolation, exhausting late-night interrogations, and repetitive badgering by police officers constitute psychological compulsion, making any forced statements legally void under Article 20(3). To ensure that the right to remain silent is meaningful, the Court introduced a vital procedural safeguard: an accused person has the right to have their defence lawyer present during police questioning. While the lawyer cannot actively disrupt the investigation or dictate responses, their physical presence acts as a structural shield against police overreach and forced confessions.

  1. Sampath Kumar v. Enforcement Officer, Enforcement Directorate (1997) – In this case, the court clarified the legal requirements of statutory summons and the right against self-incrimination under Article 20(3), ruling that statements taken under an official administrative summons carry no inherent presumption of coercion.

The Bench ruled that there is no legal or factual presumption that a statement recorded under a statutory summons is involuntary or obtained via duress. The state possesses a legitimate right to summon individuals to gather economic facts, and the procedure per se does not violate the Constitution. the Supreme Court noted that when an individual writes and signs a statement in their own hand, it actively safeguards the interests of both the department and the maker. It provides permanent physical proof of what transpired, eliminating the possibility of the accused later claiming that the agency manipulated the written record or misquoted their verbal words. The Court observed that Article 20(3) can only be triggered if actual, physical, or severe psychological coercion is proven to have occurred during interrogation.

  1. Selvi v. State of Karnataka (2010) – In this case, the court held that the forced administration of neuroscientific tests, such as Narco-Analysis, Polygraph (Lie-Detector) tests, and Brain Mapping; violates the right against self-incrimination under Article 20(3) and the right to privacy under Article 21.

The Bench ruled that these tests forcefully extract mental knowledge and conscious memories directly from the suspect’s brain. Because the results convey personal knowledge related to the crime, they have a clear “testimonial character.” Forcing a suspect to undergo them directly violates the right against self-incrimination. Moving beyond traditional physical boundaries, the Court expanded the scope of Article 21 (Right to Life and Personal Liberty) to include “mental privacy” and “cognitive liberty.” The court clarified that giving a fingerprint or a DNA sample is a purely passive physical act that does not require the brain to communicate any thoughts. In contrast, neuroscientific tests aggressively target the subject’s mental faculties and force behavioural or cognitive responses, making them strictly testimonial. The tests can only be conducted if the suspect voluntarily consents to them before a judicial magistrate, with their defence lawyer present.

  1. Tofan Singh v. State of Tamil Nadu (2020) – In this case, the court ruled that officers of the Narcotics Control Bureau (NCB) and similar enforcement agencies are “police officers” under Section 25 of the Evidence Act, making any confession made to them completely inadmissible in court; strengthening protection against self-incrimination under Article 20(3).

[Note: The Court explicitly added that while a direct confession to an NCB officer is legally dead evidence, any physical contraband, cash, or weapons discovered by the agency as a direct result of information given in that statement remains completely valid and admissible under the discovery rules of evidence law].