(1) By the evidence of persons who testify that they, from their knowledge of the witness believe him to be unworthy of credit;
(2) By proof that the witness has been bribed, or has accepted the offer of a bribe, or has received any other corrupt inducement to give his evidence;
(3) By proof of former statements inconsistent with any part of his evidence which is liable to be contradicted;
A witness declaring another witness to be unworthy of credit may not, upon his examination-in-chief, give reasons for his belief, but he may be asked his reasons in cross-examination, and the answers which he gives cannot be contradicted, though, if they are false, he may afterwards be charged with giving false evidence.
(a) A sues Â for the price of goods sold and delivered to B.
Ñ says that he delivered the goods to B.
Evidence is offered to show that, on a previous occasion, he said that he had not delivered the goods to B.
The evidence is admissible.
(b) A is indicted for the murder of B.
Ñ says the B, when dying, declared that A had given Â the wound of which he died. Evidence is offered to show that, on a previous occasion, Ñ said that the wound was not given by A or in his presence.
The evidence is admissible.
Section 155 deals with manners by which the credit of a witness may be impeached. Impeaching the credit of witness means exposing him before the court as what is real character, so that the court does not trust him. Impeaching the credit of witness may be done either by the opposite party or with the permission of court by the party who called him:
Sections dealing with impeaching credit of witness:
1. Section 155 provides for impeaching the credit of witness.
2. Impeaching the credit of a witness by cross-examination (Sections 138, 140, 145 and 154).
3. By putting questions injuring character of witness in cross-examination (Section 146).
Method of Impeaching Credit
Unworthy of Credit (Clause 1):
By producing independent witnesses from their means of knowledge and experience, they can testify that the witness if question is unworthy of credit. In order to disclose such witness as untruthful the court should be undoubtedly sure that independent witnesses are well acquainted with the general reputation of the witness. “In theory such is confined to general reputation for untruthfulness, and the witness is to state his personal opinion, but in practice the question is put in this way.”
Corrupt inducement (Clause 2):
By producing independent witness the credit of witness can be impeached that he has taken bribe, or has accepted the offer of a bribe or has received any other corrupt inducement to give evidence. When any kind of corrupt inducement is proved the witness is completely discredited.
Previous inconsistent statements (Clause 3):
This clause provides that the credit of witness may be impeached by proving his previous statements. When the present statement is contradicted by citing previous statement it must be satisfactorily proved. The previous contradictory statements of a witness can be used to discredit only his testimony and not that of other witnesses.
Previous statements recorded on tape can be used to corroborate as well as to contradict the evidence. The previous inconsistent statement must relate to the matter in issue. This third sub-clause refers to a former statement which is inconsistent with the statement made by the witness in evidence in the case and it is permissible that the witness be contradicted about that statement.
In examination-in-chief a witness can not be asked the reasons for his belief that another witness is unworthy of credit. Such questions can be asked only in cross-examination.