Impeaching credit of witness
157.  The credit of a witness may be impeached in the following ways by the adverse party or, with the consent of the court, by the party who calls him:
(a)by the evidence of persons who testify that they from their knowledge of the witness believe him to be unworthy of credit;
(b)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;
(c)by proof of former statements inconsistent with any part of his evidence which is liable to be contradicted.
[Act 4 of 2012 wef 01/08/2012]
(d)[Deleted by Act 4 of 2012 wef 01/08/2012]
    Explanation.—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 contracdicted, though, if they are false, he may afterwards be charged with giving false evidence.
Illustrations

    (a)  A sues B for the price of goods sold and delivered to B.

C 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.

C says that B, when dying, declared that A had given B the wound of which he died.
Evidence is offered to show that on a previous occasion C said that the wound was not given by A or in his presence.
The evidence is admissible.