Detention v. arrest: Beyond labels

The distinction between detention and arrest is often treated as a matter of terminology. In practice, however, it concerns something far more fundamental: the extent to which the State can deprive an individual of personal liberty while avoiding the procedural safeguards that the law attaches to an arrest.

The terms custody, detention and arrest are often used interchangeably in ordinary speech, but the law places each at a different point on the same spectrum of restraint.

'Custody' is the widest of the three. As the Supreme Court held in Niranjan Singh v. Prabhakar Rajaram Kharote, a person is in custody the moment they submit to the control of the police or the court, whether or not any formal arrest has been recorded.

‘Arrest’ is the narrowest and most consequential of the three, since it requires an accusation or suspicion of an offence and, once made, immediately triggers the full suite of Bharatiya Nagarik Suraksha Sanhita, 2023 (BNSS) safeguards.

‘Detention’ sits between the two: it is custody exercised without an accusation, whether for brief inquiry under BNSS Section 170, through the security proceedings in BNSS Sections 125 to 129, or, in its most severe executive form, under preventive detention statutes such as the National Security Act (NSA).

The Supreme Court drew the custody and arrest line most sharply in Directorate of Enforcement v. Deepak Mahajan, holding that every arrest involves custody but not every custody amounts to arrest. Further, the arrest and detention line has been drawn in State of Punjab v. Ajaib Singh, where the Court held that restraint of a person not accused of any offence falls outside the meaning of arrest under Article 22. The thin difference matters in practice precisely because each point on the spectrum carries a different and sharply diminishing set of procedural protections for the person restrained.

Arrest, per se, is not defined in any exhaustive manner under the statute. However, it is understood as a serious restraint upon an individual’s personal liberty based on an accusation or suspicion of an offence. It brings an individual within the coercive framework of criminal law and activates a series of constitutional and statutory safeguards. Arrest under the BNSS is understood as a formal act whereby a police officer or magistrate takes a person into custody on suspicion or accusation of having committed a cognizable offence, thereby initiating the criminal process and triggering a comprehensive suite of procedural rights designed to protect the accused.

Article 21 of the Constitution provides that no person shall be deprived of life or personal liberty except according to procedure established by law. Article 22 further provides specific protections to a person who has been arrested. The arrested person must be informed, as soon as may be, of the grounds of arrest, must have the right to consult and be defended by a legal practitioner of his choice and, subject to the constitutional framework, must be produced before the nearest magistrate within 24 hours of arrest. These safeguards are not procedural formalities. They are constitutional limitations on the State's power to deprive an individual of liberty. The statutory framework under the BNSS also regulates the circumstances in which arrest may be made and prescribes safeguards surrounding the process.

Detention is also not defined as a general wide term in the BNSS, but is understood through its usage in provisions relating to temporary custody for inquiry, preventive measures and security proceedings under the broader criminal law framework. This power is often employed as a short-term detention for inquiry rather than formal arrest, reflecting the preventive rather than punitive nature of such restraint. The closest the BNSS comes to defining the word is Section 301(a), which appears in Chapter XXIV (Attendance of Persons Confined or Detained in Prisons). For the limited purposes of that Chapter alone, the Section provides that ‘detained’ includes detained under any law providing for preventive detention. This confirms, at the level of the statutory text itself, that preventive detention is treated as a form of ‘detention’ distinct from formal arrest, even though the definition is chapter specific and not a general definition applicable to the whole Sanhita.

The distinction between arrest and detention can be understood through four key aspects: purpose, legal authority, duration and the rights available to the person restrained.

First, the purpose differs. Arrest is generally accusatory and investigatory, following suspicion of or involvement in a cognizable offence. It seeks to secure the accused, facilitate investigation, prevent further offences, or ensure appearance before the court. Detention, particularly preventive detention and security proceedings under the BNSS, is primarily precautionary and forward-looking, aimed at preventing an anticipated threat to public order or security. Even detention under Section 170 BNSS seeks to prevent an imminent cognizable offence rather than punish a past one.

Second, the legal authority differs. Arrest is regulated by Sections 35 to 62 BNSS, which prescribe the circumstances and procedure for lawful arrest and safeguards concerning the arrest memorandum, informing relatives or friends and communicating the grounds of arrest and right to bail. Preventive detention and security proceedings derive authority from Sections 125 to 143 & Sections 168 to 172 BNSS and special statutes such as the NSA, operating under a distinct framework of executive or judicial oversight.

Third, duration is significant. An arrested person must ordinarily be produced before a magistrate within 24 hours, excluding travel time, ensuring prompt judicial scrutiny. Preventive detention under special legislation may continue for substantially longer periods, subject to statutory safeguards and review. Detention under Section 170 BNSS, however, is ordinarily limited to 24 hours unless further detention is authorised by law.

Fourth, the rights available differ. An arrested person enjoys safeguards concerning the grounds of arrest, communication with relatives or friends, legal representation, bail where applicable, medical examination and protection against custodial violence. A preventive detainee is entitled under Article 22(5) to be informed of the grounds of detention and to make a representation, but does not enjoy the same procedural rights as an accused facing ordinary criminal prosecution. Thus, arrest forms part of the criminal justice process, while preventive detention is an exceptional measure requiring careful judicial scrutiny to prevent abuse of State power.

The concept of informal detention raises particularly serious concerns. Consider a situation in which a person is called to a police station for questioning in the morning and remains there until late at night. The police maintain that the person was never arrested. Yet, the person was not permitted to leave, was continuously questioned and was effectively under police control. The State cannot be permitted to create a category of "informal custody" in which a person is deprived of liberty but does not receive the safeguards available to an arrested person. At the same time, courts must be careful not to create an overly broad test that treats every interaction with the police as an arrest. Investigation necessarily involves questioning, information gathering and interaction with witnesses and suspects.

The Supreme Court has, across decades and across contexts, consistently affirmed that personal liberty cannot be curtailed by labels, routine police action, or procedural shortcuts. This principle runs through DK Basu, Joginder Kumar, Arnesh Kumar, Mihir Rajesh Shah and so many more on the arrest side. In the specific context of preventive detention, through recent Article 22(5) jurisprudence such as Jaseela Shaji v. Union of India, the Court held that even a preventively detained person's rights to be furnished the material relied upon and to have a representation decided without delay, cannot be diluted merely because the detention is termed preventive rather than punitive.

Recently, there were several reported incidents of detention of protesting students without formal arrest across several police stations in the country. Moreover, on July 28, 2026, a Bench of the Supreme Court, while hearing petitions arising out of police action against the protesting students, directed,

“All States are hereby instructed to release children under the age of 18, who have been reported to be arrested or detained in connection with the ongoing protests and who do not possess any criminal antecedents.”

The distinction between detention and arrest should, therefore, not become a loophole through which constitutional safeguards can be postponed. The question is simple but fundamental: was the person actually free to leave? The answer to that question, considered alongside the statutory framework and the surrounding circumstances, may often be more constitutionally significant than whether the police chose to call the restraint an "arrest", a "detention", or merely an "inquiry" or “custody”. In a constitutional democracy, the protection of liberty must depend on what the State actually does to a person and not on what it chooses to call that action.

Prafull Bhardwaj and Shubhi Singh are advocates practising before the Supreme Court of India.