The Finality Rule under Section 156 of the Bharatiya Sakshya Adhiniyam, 2023: Exclusion of Evidence to Contradict Answers Testing Veracity

A cross-examiner may ask a witness almost anything about his character. What he may not do is prove it. Section 156 provides that where a question was relevant only as tending to shake credit, and the witness has answered it, no evidence may be given to contradict him — the answer is final. The rule exists because every collateral imputation would otherwise generate its own subsidiary trial, and a case about a contract would end up deciding whether a witness was dismissed for dishonesty fifteen years ago.

1. The Provision

Section 156, BSA — Exclusion of evidence to contradict answers to questions testing veracity

When a witness has been asked and has answered any question which is relevant to the inquiry only in so far as it tends to shake his credit by injuring his character, no evidence shall be given to contradict him; but, if he answers falsely, he may afterwards be charged with giving false evidence.

Exception 1. — If a witness is asked whether he has been previously convicted of any crime and denies it, evidence may be given of his previous conviction.

Exception 2. — If a witness is asked any question tending to impeach his impartiality, and answers it by denying the facts suggested, he may be contradicted.

Section 156 corresponds to Section 153 of the Indian Evidence Act and is carried forward unchanged. Because of the consolidation of three provisions into Section 146, this part of the chapter runs three numbers higher than the earlier Act.

2. The Illustrations

The four illustrations to the section do more to explain it than any paraphrase, and the third is the one that matters.

	The facts	The result
(a)	A claim against an underwriter is resisted on the ground of fraud. The claimant is asked whether, in a former transaction, he had not made a fraudulent claim. He denies it. Evidence is offered to show that he did	The evidence is inadmissible
(b)	A witness is asked whether he was not dismissed from a situation for dishonesty. He denies it. Evidence is offered to show that he was	The evidence is not admissible
(c)	A affirms that on a certain day he saw B at one city. A is asked whether he himself was not on that day at another city. He denies it. Evidence is offered to show that A was at the other city that day	The evidence is admissible — not as contradicting A on a fact affecting his credit, but as contradicting the alleged fact that B was seen where A says
(d)	A is asked whether his family has not had a blood feud with the family of B, against whom he gives evidence. He denies it	He may be contradicted, the question tending to impeach his impartiality

In each case, the section adds, the witness might if he answered falsely have been charged with giving false evidence.

⚠ Illustration (c) is the whole test in miniature

The question in (c) — were you not in another city that day? — looks like an attack on the witness's truthfulness, and in one sense it is. But it is also relevant on its own account: if A was elsewhere, then A did not see B where he says he did, and the fact deposed to falls. Because the matter is relevant otherwise than as going to credit, the contradiction is permitted. The test the illustration supplies is therefore: would this material have been admissible apart from its effect on the witness's credibility? If yes, contradict; if no, the answer is final.

3. The Test — Collateral or Not

The operative words are 'relevant to the inquiry only in so far as it tends to shake his credit'. Everything turns on the word only.

Question	Relevant apart from credit?	May the answer be contradicted?
Whether the witness was present at the place of the occurrence	Yes — it goes to whether he saw what he says	Yes, under Section 143
Whether the light was sufficient to recognise the accused	Yes — it goes to the reliability of the identification	Yes
Whether the witness has been dismissed for dishonesty	No — it bears only on whether he is to be believed	No — illustration (b)
Whether the witness made a fraudulent claim in an unrelated transaction	No	No — illustration (a)
Whether the witness has a blood feud with the party against whom he deposes	No, but it goes to impartiality	Yes — Exception 2, illustration (d)
Whether the witness has been previously convicted, and he denies it	No, but it is expressly excepted	Yes — Exception 1

The rule is sometimes stated as 'the answer to a collateral question is final'. That formulation is accurate provided 'collateral' is understood as the section defines it — a matter relevant only because it affects the witness's credit.

4. Why the Rule Exists

Three reasons support it, and they are worth stating because they also explain the two exceptions.

It prevents subsidiary trials. If every imputation could be proved, the court would have to decide, within the main case, whether the witness was in fact dismissed for dishonesty — which would require its own witnesses, its own cross-examination, and its own findings. Multiplied across a dozen witnesses, the main issue would disappear.

It protects the witness. A person who comes to court to give evidence about somebody else's dispute should not find his own past put on trial. He has no standing to defend himself, no pleadings, and no remedy.

It reflects proportion. Collateral matters bear on credibility only indirectly, and the cost of establishing them almost always exceeds their value to the decision.

The exceptions are explicable on the same reasoning. A previous conviction requires no subsidiary trial — it is proved by a certified copy of the judgment, which takes a moment and admits of no dispute. And partiality is not truly collateral at all: a witness with a blood feud against the party has a reason to lie about the very matter in hand, and that bears directly on the reliability of his account.

5. The Two Exceptions

5.1 Previous conviction denied

Where a witness is asked whether he has been previously convicted of any crime and denies it, evidence may be given of the conviction.

Three conditions are contained in it. The question must have been asked; the witness must have denied; and what may then be proved is the conviction, not the underlying conduct. A witness who admits the conviction cannot be contradicted, there being nothing to contradict.

The conviction is proved as a public document — by a certified copy of the judgment under Sections 74 to 77, with the presumption of genuineness in Section 78. This connects with Section 158(c), which permits credit to be impeached by proof of former inconsistent statements, and with the general position that a judgment is relevant under Section 37 as to its existence.

5.2 Impartiality falsely denied

Where a witness is asked a question tending to impeach his impartiality, and answers by denying the facts suggested, he may be contradicted.

This is the wider and more useful of the two. What it covers is any material showing that the witness has a reason to favour one side.

Enmity with the party against whom he deposes — illustration (d), the blood feud.
Relationship or interest in the outcome, where denied.
Bribery or corrupt inducement, which is separately a ground of impeachment under Section 158(b).
A prior connection with a party which he has denied — employment, a business relationship, a debt.

⚠ Exception 2 overlaps with Section 158(b) and should be pleaded with it

Where the suggestion is that the witness has been bribed or has received a corrupt inducement, two provisions permit proof: Exception 2 to Section 156, because the question tends to impeach his impartiality and he has denied it; and Section 158(b), which independently permits proof of bribery as a mode of impeaching credit. Both should be relied upon, since Section 158(b) does not require the matter to have been put and denied, while Exception 2 does.

6. Section 156 and Section 158 Read Together

The two sections are the negative and positive halves of the same subject, and they are frequently cited without noticing the relationship.

	Section 156	Section 158
What it says	Where the question went only to credit and was answered, no evidence may contradict	Credit may be impeached in three enumerated ways
Direction	Prohibitory — the general rule	Permissive — the exceptions
Relationship	States the silence	Names what may break it
The link	Exceptions 1 and 2	Clause (c) is expressly limited to evidence 'liable to be contradicted', which imports Section 156

The words in Section 158(c) — former statements inconsistent with any part of his evidence 'which is liable to be contradicted' — are the hinge. A former inconsistent statement may be proved only where the evidence it contradicts is itself capable of being contradicted, which takes one straight back to Section 156. A contradiction on a fact in issue may always be proved; a contradiction on a collateral matter may not, unless an exception applies.

7. What Remains Available

The rule forecloses proof, not everything. Four things survive and are worth remembering, because a cross-examiner who obtains a denial on a collateral matter has not necessarily wasted his time.

The question and the answer are on the record. The court has heard the imputation put and the denial given, and may form its own view of the witness's demeanour in answering.

A prosecution for false evidence remains. The section says so expressly — if the witness answers falsely he may afterwards be charged with giving false evidence. This is the residual sanction, and it is why the rule is not an invitation to lie.

The other modes of impeachment under Section 158 are untouched where they apply — evidence that the witness is unworthy of credit under clause (a), and proof of bribery under clause (b), neither of which depends on the matter having been put and denied.

The court's assessment of credibility is unaffected. Section 156 governs what may be proved; it does not require the court to believe a witness whose answers were evasive.

⚠ But weigh the cost before putting it

A collateral imputation put and denied cannot be proved, so the cross-examiner has damaged the witness only to the extent that the court thinks the denial unconvincing. Against that must be set Section 152, which requires reasonable grounds; Section 153, which permits a report where there were none; and the risk that an imputation that visibly failed will reflect on the party who made it. Putting a scandalous suggestion one cannot prove is a real tactical decision, not a free hit.

8. Practical Points

Before offering evidence to contradict, ask the illustration (c) question — would this material have been admissible apart from its effect on credit?
If yes, do not argue Section 156 at all. The matter is not collateral, and the contradiction is permitted under Section 143.
If no, identify an exception — a denied previous conviction, or a denial going to impartiality.
To use Exception 1, put the conviction and obtain a denial, then prove it by certified copy under Sections 74 to 77 with the presumption in Section 78.
To use Exception 2, frame the question as going to impartiality, and put the facts specifically so that a denial engages the exception.
Plead Section 158(b) alongside Exception 2 where bribery is alleged, since it does not require the matter to have been put.
As opposing counsel, take the Section 156 objection when the contradicting evidence is tendered, not when the question is asked.
Remember Section 152. A collateral imputation still needs reasonable grounds, even though it can never be proved.

9. The Position Stated Shortly

Where a question was relevant only as tending to shake credit and has been answered, no evidence may contradict the answer.
The word 'only' carries the rule. A matter relevant apart from credit may always be contradicted.
Illustration (c) supplies the test — whether the material would have been admissible apart from its effect on credibility.
The rule prevents subsidiary trials, protects the witness, and reflects proportion.
Exception 1 — a denied previous conviction may be proved, being provable at once by certified copy.
Exception 2 — a question impeaching impartiality, falsely denied, may be contradicted; partiality is not truly collateral.
Section 158(c) imports the rule by the words 'liable to be contradicted'.
A false answer remains punishable as giving false evidence, which is the residual sanction.

10. Related Topics and Provisions

Topic or provision	Connection
Questions Lawful in Cross-Examination — Section 149	The credit questions this section limits
Impeaching the Credit of a Witness — Section 158	The permissive half of the same subject
Questions Without Reasonable Grounds — Sections 152 and 153	Why a collateral imputation still needs a basis
Cross-Examination as to Previous Statements in Writing — Section 148	Contradiction where the matter is not collateral
Indecent, Scandalous and Insulting Questions — Sections 154 and 155	The court's control over the manner of questioning
Public and Private Documents — Sections 74 to 77	Proving a previous conviction by certified copy
Examination of Witnesses — Sections 140 to 168	The chapter as a whole