9. (1) A party producing a witness shall not be allowed to impeach his credit by general evidence of bad character, but if the witness, in the opinion of the court, proves adverse, the party may contradict him by other evidence, or, by leave of the court, may prove that the witness made at other times a statement inconsistent with his present testimony, but before the last mentioned proof can be given the circumstances of the supposed statement, sufficient to designate the particular occasion, shall be mentioned to the witness, and he shall be asked whether or not he did make the statement.
"Adverse" is taken to mean that the witness "opposed in interests". This is in distinction with the traditional meaning of "adverse" requiring outward hostility, such as a witness who is belligerent argumentative and un-cooperative, rather than simply hostility in mind. Adversity can be found by way of many means including demeanor or a prior contradictory statement. Testifying in an unfavourable way contrary to a prior statement can be enough.
An "hostile" witness, by contrast, is a subset of "adverse" witnesses. A hostile witness is one who is "not giving her evidence fairly and with a desire to tell the truth because of a hostile animus towards the [calling party]" This will capture those witnesses who are belligerent or argumentative. A hostile witness will also engage s.9(1).
An application under s. 9(1) is to be performed without the presence of the jury as a voir dire.
Section 9(1) further provides that before counsel can attempted to contradict a witness with a previous statment, counsel has the obligation to first mention the circumstances of the statement to the witness, including the particularities of the occasion it was made, and confirm with the witness whether the statement was made by him.
Where the court gives permission to cross examination, the counsel may impeach the witness. Counsel may not use it to bolster favourable evidence from the witness.
Section 9(1) does not permit counsel to cross examine at large. It is only an ability to cross examine on the circumstances of the prior statement. Only a declaration of hostility permits cross examination at large.
Whenever there is an application under s.9, the applicant must inform the judge what the purpose of tending the prior statement.