Mens rea

Mens rea is the mental element of an offence. It comes from the maxim actus non facit reum nisi mens sit rea, an act does not make a person guilty unless the mind is also guilty. A crime ordinarily needs both a prohibited act or omission, the actus reus, and a blameworthy state of mind, the mens rea. The degree of mental fault varies from offence to offence: intention, knowledge, reason to believe, dishonesty, fraud, rashness or negligence.

The BNS does not state a general principle of mens rea. Instead, each offence carries its own mental element in words that the Sanhita defines. Section 2(7) defines dishonestly as acting with the intention of causing wrongful gain or wrongful loss, Section 2(9) defines fraudulently as acting with intent to defraud, Section 2(29) explains reason to believe, and Section 2(33) explains voluntarily as causing an effect by means intended to cause it, or known or with reason to believe to be likely to cause it. The general exceptions in Chapter III, such as mistake of fact, accident, infancy and unsoundness of mind, work largely by negativing mens rea.

Mens rea is presumed to be an ingredient of every offence unless the statute expressly or by necessary implication excludes it. Some regulatory and public welfare offences impose strict liability, and in State of Maharashtra v. M.H. George (1965) the Supreme Court held that mens rea was excluded for an offence under foreign exchange law. Courts read mens rea into speech offences: in Imran Pratapgadhi v. State of Gujarat (2025) the Court held that mens rea must be read into Section 196 of the BNS, as it was into Section 153A IPC. In Jacob Mathew v. State of Punjab the Court held that negligence becomes criminal only when it is gross, so that the element of mens rea is shown.

Mens rea should be kept apart from motive, which is the reason for an act and is generally not an element of the offence. Examiners ask the meaning of the term, its link with actus reus, and when statutes exclude it.