Protection in respect of conviction for offences

Polity & Governance glossary

Also called: Article 20 · Topic: Fundamental Rights and Constitutional Remedies · NCERT: Class 11, Ch 2 "Rights in the Indian Constitution"

Meaning

Protection in respect of conviction for offences (Article 20) gives every person facing a criminal charge three shields:

No ex post facto criminal law: no punishment under a law made after the act was done.
No double jeopardy: no one can be prosecuted and punished twice for the same offence.
No self-incrimination: no accused person can be forced to be a witness against themselves.

These shields cover citizens, foreigners and companies alike. Since the 44th Amendment, 1978, Article 20 cannot be suspended even during a National Emergency, along with Article 21. This makes it one of the strongest guarantees of a fair criminal process in Part III of the Constitution.

Explanation

Who is protected and how strong the protection is

Every person is protected, not only citizens.
This includes foreigners and companies (legal persons).
NCERT (Class 11, Ch 2) calls these the "rights of the accused".
Emergency-proof:
Normally, during a National Emergency, the President can suspend the right to go to court to enforce Fundamental Rights (Article 359).
The 44th Amendment, 1978 says this cannot be done for Articles 20 and 21.

Art. 20(1): No ex post facto criminal law

An ex post facto law is a law that reaches back in time and punishes an act done before the law existed.
Art. 20(1) bars two things:
Conviction for an act that was not a crime when it was done.
A heavier penalty than the law allowed at the time of the act.
Limits:
It covers criminal laws only. Civil and tax laws can be retrospective (they can apply to the past).
It bars only conviction and sentence. A trial can still follow a new procedure.
A change that helps the accused, such as a lighter penalty, can apply to past acts (Rattan Lal v. State of Punjab, 1965).

Art. 20(2): No double jeopardy

Double jeopardy means being tried and punished twice for the same offence. Art. 20(2) bars it.
All of these conditions must be met for the bar to apply:
There was an earlier prosecution and punishment.
Both cases are for the same offence.
The earlier case was before a court or judicial tribunal.
Limit: it does not cover departmental inquiries or proceedings under the Sea Customs Act (Maqbool Hussain v. State of Bombay, 1953).
So a government servant can face both a criminal trial and a disciplinary inquiry for the same act.

Art. 20(3): Right against self-incrimination

No person accused of an offence can be forced to be a witness against themselves.
What it covers: only testimonial compulsion, meaning being forced to give personal knowledge by speaking or writing.
What it does not cover: physical evidence. Fingerprints, thumb impressions, handwriting and blood samples can be taken because they are not "testimony" (State of Bombay v. Kathi Kalu Oghad, 1961).
When it starts: at the police interrogation stage, not only in court.
An accused may stay silent when the answers could incriminate them (Nandini Satpathy v. P.L. Dani, 1978).
Scientific tests: these include narco-analysis (questioning a suspect after giving a drug such as sodium pentothal that lowers self-control), polygraph (lie-detector) and brain-mapping (BEAP).
If done without consent, they break Art. 20(3) and the mental privacy protected by Art. 21 (Selvi v. State of Karnataka, 2010).
They are allowed only with consent.
Their results cannot be used as evidence on their own. Only facts found later because of a voluntary test can be used.

In the Constitution and practice

Where it sits: Article 20 is in Part III (Fundamental Rights). It is grouped with Article 21 (life and personal liberty) and Article 22 (arrest and detention).
44th Amendment, 1978: it made Arts. 20 and 21 safe from suspension under Article 359. This was a response to the Emergency of 1975-77.
Who relies on it: accused persons, the courts that try them, and the police and investigating agencies, who must respect it during questioning.
Landmark cases:

Case	Year	Principle
Maqbool Hussain v. State of Bombay	1953	Departmental or Sea Customs proceedings are not "prosecution and punishment". No double jeopardy bar.
State of Bombay v. Kathi Kalu Oghad	1961	Fingerprints, handwriting and blood samples are not testimony. Art. 20(3) is not broken.
Rattan Lal v. State of Punjab	1965	A law that helps the accused can apply to past acts.
Nandini Satpathy v. P.L. Dani	1978	The right to silence applies at the police interrogation stage.
Selvi v. State of Karnataka	2010	Narco-analysis, polygraph and brain-mapping without consent break Arts. 20(3) and 21.

New pressure point: the Criminal Procedure (Identification) Act, 2022:
It replaced the Identification of Prisoners Act, 1920.
It lets police collect "measurements": finger and palm prints, iris and retina scans, physical and biological samples, and behavioural traits such as signatures.
It covers even some persons who have only been arrested.
Critics say it stretches the Kathi Kalu Oghad line and the right to privacy (Puttaswamy, 2017).

Don't confuse with

Article 22 (protection against arrest and detention): Art. 22 protects a person at the time of arrest (grounds of arrest, a lawyer, production before a magistrate within 24 hours). Art. 20 protects a person during criminal charge, trial and punishment. Art. 22's safeguards do not cover enemy aliens or preventive detainees. Art. 20 covers every person.
Retrospective civil or tax laws: these are allowed. Only retrospective criminal laws that convict someone or increase a penalty are barred by Art. 20(1).
Departmental inquiry vs criminal prosecution: a disciplinary inquiry is not "prosecution and punishment" by a court. So facing both for the same act does not break Art. 20(2) (Maqbool Hussain, 1953).
Physical evidence vs testimonial compulsion: taking fingerprints or blood samples is allowed (Kathi Kalu Oghad, 1961). Forcing statements, or using narco tests without consent, is barred (Selvi, 2010).

Prelims Hooks

44th Amendment, 1978: Arts. 20 and 21 cannot be suspended during a National Emergency (Art. 359).
Art. 20(1) bars retrospective criminal laws only. Civil and tax laws can be retrospective. A law that helps the accused can apply to the past (Rattan Lal, 1965).
Art. 20(2): double jeopardy does not cover departmental inquiries (Maqbool Hussain, 1953).
Kathi Kalu Oghad (1961): taking fingerprints, thumb impressions, handwriting or blood samples does not break Art. 20(3).
Selvi (2010): narco-analysis, polygraph and brain-mapping without consent break Arts. 20(3) and 21.
Trap: Article 20 protects every person, including foreigners and companies, not only citizens.

Mains Points

Fair trial vs effective investigation:
Art. 20(3) stops forced confessions. It also protects the right to silence from the police stage onward (Nandini Satpathy, 1978).
Agencies say scientific tests help solve crimes. Selvi (2010) settled the balance: such tests are allowed only with consent, and their results are not evidence on their own.
New technology and old limits:
The Criminal Procedure (Identification) Act, 2022 allows wide collection of biometric and biological data, even from some arrested persons.
This tests whether the 1961 line between "physical" and "testimonial" evidence still works in an age of data.
Reform options: clear limits on how long data can be kept, consent safeguards and a privacy check in line with Puttaswamy (2017).
A right that cannot be suspended:
The Emergency of 1975-77 showed how liberty can be suspended.
By putting Arts. 20 and 21 beyond Art. 359, the 44th Amendment, 1978 created a core of criminal-justice rights that the state cannot switch off, even in a crisis.

Related concepts

Rights of the accused and detenus: Articles 20 and 22, and the NHRC

Sources

1Class 11, Ch 2 "Rights in the Indian Constitution" (primary)