V.I. Thankappan v. State of Kerala: the BNSS protection for accused with intellectual disability applies retrospectively

The facts of V.I. Thankappan v. State of Kerala are spare and consequential. The petitioner was a 74-year-old man. He was facing prosecution under §Section 13 of the Prevention of Corruption Act, 1988. The Consultant Neurologist at the District Hospital, Palakkad, diagnosed him with Alzheimer's Dementia — a progressive condition characterised by deterioration in memory, language, and the capacity to engage with structured information.

The question before Justice K. Babu of the Kerala High Court was whether the trial against him could continue, and — if it could not — what the procedural framework for the postponement should be. The judgment was delivered on 5 September 2024, two months after the Bharatiya Nagarik Suraksha Sanhita had replaced the Code of Criminal Procedure on 1 July 2024.

The framework: CrPC and BNSS compared

The protection for accused unable to defend themselves due to mental incapacity has a long lineage in Indian criminal procedure. Sections 328 to 330 of the CrPC, which the BNSS now replaces with Sections 367 to 369, established the framework: where the accused is of "unsound mind" or suffers from "mental retardation" such that he is incapable of making his defence, the trial is to be postponed and the accused dealt with under a specific procedural framework — including, in appropriate cases, transfer to a mental-health establishment and periodic review of capacity.

The CrPC language was old. "Mental retardation" was a clinical term that had largely fallen out of use in modern psychiatric practice. The category did not, on its plain language, extend to conditions such as dementia, autism-spectrum disorders, and other forms of intellectual or cognitive impairment that did not fit either "unsound mind" or "mental retardation" cleanly.

The BNSS modernises the framework. The successor provisions — Sections 367 to 369 BNSS — extend protection to accused suffering from "intellectual disability," a broader and clinically more current category. The framework otherwise tracks the CrPC: where the accused, by reason of intellectual disability, is unable to make his defence, the trial is to be postponed, and the accused dealt with under the specified procedures.

The clinical change is doctrinally significant. "Intellectual disability" encompasses conditions — Alzheimer's dementia, frontotemporal dementia, severe traumatic brain injury, autism with associated communication impairment — that were on the boundary of "unsound mind" under the CrPC framework. The BNSS settles the question by name.

The holding

The reasoning

The doctrinal architecture of the judgment has three connected threads.

The constitutional anchor: fair trial under Article 21

The first thread is constitutional. The right to a fair trial is part of the Article 21 guarantee — a proposition established in the post-Maneka Gandhi doctrinal expansion and reinforced in successive judgments on procedural fairness. A trial in which the accused is not in a position to engage with the proceedings — to understand the charge, to instruct counsel, to give evidence in his defence — is not a fair trial within the meaning of Article 21.

The Bench's reading is that this constitutional protection is not procedure-specific. Whether the procedural framework is the CrPC's or the BNSS's, the underlying constitutional protection is the same. Where the CrPC framework is insufficient to capture the accused's actual condition — because the clinical category in which the accused falls (dementia) is not within the CrPC's old language — the BNSS framework, which does capture it, must be applied to give effect to the constitutional protection.

The retrospective-application doctrine

The second thread is the application of procedural provisions to ongoing proceedings. The general rule in Indian criminal procedure is that procedural changes apply prospectively unless the contrary is clear. The Bench's reading is that the BNSS protection for accused with intellectual disability is a procedural provision — it does not create new substantive offences, does not modify the elements of existing offences, and does not affect any vested right of the prosecution or the accused. It is, accordingly, available to be applied to ongoing proceedings under the principle that beneficial procedural reform extends to pending matters.

The doctrinal posture is consistent with the Supreme Court's approach in earlier cases involving beneficial procedural reforms: where the new framework better protects the rights of the accused, the framework's application to pending proceedings is the constitutional expectation, not the exception.

The clinical evidence and capacity determination

The third thread is procedural. The neurologist's diagnosis at the District Hospital was, on the record, the basis for the capacity determination. The Bench treated the medical evidence as sufficient to engage the BNSS framework; it did not require additional or independent expert evaluation as a prerequisite to postponement.

This procedural latitude is important. The BNSS framework — like its CrPC predecessor — contemplates an inquiry by the court into the accused's capacity. Where the medical evidence is unambiguous, the inquiry need not be elaborate. Where it is contested, the framework permits further inquiry. The Kerala High Court's reading does not displace the inquiry; it ensures that the inquiry is conducted in a manner that respects the accused's clinical reality.

What the framework looks like in practice

The procedural architecture of the BNSS protection, applied to a case like Thankappan, has the following sequence:

1. Trigger: The court is informed — by the accused, by counsel, by medical professionals, or on its own observation — that the accused may be suffering from a condition rendering him incapable of making his defence.

2. Capacity inquiry: The court directs medical examination of the accused. The examination should be by a clinical professional with relevant expertise in the condition in issue. Where the condition is dementia, a neurologist or geriatric psychiatrist is the appropriate expert. The court considers the medical report and any other relevant material on the question of capacity.

3. Postponement: Where the court finds that the accused, by reason of the disability, is incapable of making his defence, the trial is postponed. The postponement is not a discharge — the proceedings remain pending, subject to the periodic review framework.

4. Periodic review: The framework contemplates periodic reassessment of the accused's capacity. Where the accused recovers capacity (in conditions where recovery is possible) or where new clinical information bears on the capacity question, the matter can be brought back before the court.

5. Other procedural directions: Where appropriate, the court may make directions regarding the accused's care during the postponement — including, in cases of dementia, ensuring that the accused is in an appropriate care setting and that the care arrangements are sustainable.

The reach of the judgment

The Kerala HC reading has been picked up — in trial-court practice across the country — as the doctrinal framework for how the BNSS intellectual-disability protection operates in cases that straddle the 1 July 2024 transition. Three categories of practitioner work flow from it.

For the criminal defence bar

Where a client suffers from a condition that may bear on capacity — dementia, severe depression with cognitive impairment, autism, traumatic brain injury with persisting cognitive effects — the BNSS framework is now the doctrinal anchor. The Kerala HC judgment provides the authority for the proposition that the wider category of "intellectual disability" is available even where the proceedings were initiated under the CrPC. The plea should be made at the earliest stage at which the clinical evidence is sufficient to engage the inquiry.

For the prosecution

The capacity question is not, on the BNSS framework, an obstacle to legitimate prosecution. Where the medical evidence does not support a finding of incapacity, the trial continues. Where it does, the framework provides for postponement and periodic review — not discharge or acquittal. The prosecution's institutional interest in seeing serious offences tried is preserved by the architecture; what changes is that the architecture now better captures the clinical reality of accused who may genuinely lack capacity.

For the bench

The trial court is now operating under a framework that requires substantive engagement with the capacity question where it is properly raised. The Kerala HC's reading suggests that the medical evidence should be assessed on its substantive merits, not on a procedural test of formal sufficiency. Where the evidence is unambiguous — as it was in Thankappan — the postponement should follow.

What the judgment did not decide

It is worth being precise about the boundaries.

• The judgment does not foreclose ongoing investigation. Postponement of trial does not, of itself, terminate the underlying proceedings; the prosecution can continue to gather evidence subject to the framework's restrictions on the participation of the accused.
• The judgment does not address the standard of proof for the capacity determination. Where the medical evidence is contested, the framework requires inquiry but does not lay down a specific evidentiary standard.
• The judgment does not address the position where the accused recovers capacity after a substantial postponement period. The periodic review framework contemplates the question but does not specify the criteria for resumption of trial in cases where capacity has returned.

These boundary questions are likely to be developed in further High Court and Supreme Court engagement with the section.

The bottom line

V.I. Thankappan is a short judgment with a clear holding: the BNSS's wider protection for accused with intellectual disability, including dementia, applies retrospectively to proceedings initiated under the CrPC. The doctrinal architecture is Article-21-grounded, the procedural mechanism is the BNSS framework, and the practical effect is a substantial improvement in how Indian criminal procedure deals with accused whose clinical reality the older CrPC language did not capture. For the criminal bar, the judgment is the leading authority on the section's transitional application — and for the bench, it sets the analytical posture for how the inquiry into capacity should be conducted.

Verify against the reported judgment. The framework for periodic review and the criteria for resumption of trial are likely to be the subject of further appellate development.