Clause (3) of Article 20 provides that no person accused of any offence shall be compelled to be a witness against himself. Thus Article 20(3) embodies the general principles of English and American jurisprudence that no one shall be compelled to give testimony which may expose him to prosecution for crime. The cardinal principle of criminal law which is really the bed rock of English jurisprudence is that an accused must be presumed to be innocent till the contrary is proved . It is the duty of the prosecution to prove the offence. The accused need not make any admission or statement against his own free will. The fundamental rule of criminal jurisprudence against self-incrimination has been raised to a rule of constitutional law in Article 20(3).The guarantee extends to any person accused of an offence and prohibits all kinds of compulsions to make him a witness against himself. Explaining the scope of this clause in M.P. Sharma v. Satish Chandra , the Supreme Court observed that this right embodies the following essentials:
(a) It is a right pertaining to a person who is ” accused of an offence.”
(b) It is a protection against ” compulsion to be a witness”.
(c)It is a protection against such compulsion relating to his giving evidence ” against himself.”In Nandini Satpathy v. P.L. Dani , the Supreme Court has considerably widened the scope of clause (3) of Article 20. The Court has held that the prohibitive scope of Article 20(3) goes back to the stage of police interrogation not commencing in court only. It extends to, and protects the accused in regard to other offences-pending or imminent, which may deter him from voluntary disclosure. The phrase compelled testimony’ ‘must be read as evidence procured not merely by physical threats or violence but by psychic (mental) torture, atmospheric pressure, environmental coercion, tiring interrogatives, proximity, overbearing and intimidatory methods and the like. Thus, compelled testimony is not limited to physical torture or coercion, but extend also to techniques of psychological interrogation which cause mental torture in a person subject to such interrogation.

Right to silence is also available to accused of a criminal offence. Right to silence is a principle of common law and it means that normally courts tribunal of fact should not be invited or encouraged to conclude, by parties or prosecutors, that a suspect or an accused is guilty merely because he has refused to respond to question put to him by the police or by the Courts. The prohibition of medical or scientific experimentation without free consent is one of the human rights of the accused . In case of Smt. Selvi & Ors. v. State of Karnataka & Ors. , wherein the question was- Whether involuntary administration of scientific techniques namely Narcoanalysis, Polygraph (lie Detector) test and Brain Electrical Activation Profile (BEAP) test violates the ‘ right against self- incrimination’ enumerated in Article 20(3) of the Constitution. In answer, it was held that it is also a reasonable restriction on ‘ personal liberty’ as understood in the context of Article 21 of the Constitution. Following observations were made in this landmark case:
(i) No individual should be forcibly subjected to any of the techniques in question, whether in the context of investigation in criminal cases or otherwise. Doing so would amount to an unwarranted intrusion into personal liberty.
(ii) Section 53, 53-A and 54 of Criminal Procedure Code permits the examination include examination of blood, blood-stains, semen swabs in case of sexual offences, sputum and sweat, hair samples and finger nail dipping by the use of modern and scientific techniques including DNA profiling. But the scientific tests such as Polygraph test, Narcoanalysis and BEAF do not come within the purview of said provisions.
(iii) It would be unjustified intrusion into mental privacy of individual and also amount to cruel, inhuman or degrading treatment.
(a) Voluntary administration of impugned techniques are, however, permissible subject following safeguards, but test results by themselves cannot be admitted in evidence.
(b) No Lie Detector Tests should be administered except on the basis of consent of the accused. An option should be given to the accused whether he wishes to avail such test.
(c) If the accused volunteers for a Lie Detector Test, he should be given access to a lawyer and the physical, emotional and legal implication of such a test should be explained to him by the police and his lawyer.
(d) The consent should be recorded before a Judicial Magistrate.

(e) During the hearing before the Magistrate, the person alleged to have agreed should be duly represented by a lawyer.
(f) At the hearing, the person in question should also be told in clear terms that the statement that is made shall not be a ‘confessional’ statement to the Magistrate but will have the status of a statement made to the police.
(g) The Magistrate shall consider all factors relating to the detention including the length of detention and the nature of the interrogation.
(h) The actual recording of the Lie Detector Test shall be done by an independent agency (such as a hospital) and conducted in the presence of a lawyer.
(i) A full medical and factual narration of the manner of the information received must be take