(1) If the determination of a question whether--(a) evidence should be admitted (whether in the exercise of a discretion or not), or(b) evidence can be used against a person, or(c) a witness is competent or compellable,depends on the court finding that a particular fact exists, the question whether that fact exists is, for the purposes of this section, a preliminary question.
(2) If there is a jury, a preliminary question whether--(a) particular evidence is evidence of an admission, or evidence to which section 138 (Discretion to exclude improperly or illegally obtained evidence) applies, or(b) evidence of an admission, or evidence to which section 138 applies, should be admitted,is to be heard and determined in the jury's absence.
(3) In the hearing of a preliminary question about whether a defendant's admission should be admitted into evidence (whether in the exercise of a discretion or not) in a criminal proceeding, the issue of the admission's truth or untruth is to be disregarded unless the issue is introduced by the defendant.
(4) If there is a jury, the jury is not to be present at a hearing to decide any other preliminary question unless the court so orders.
(5) Without limiting the matters that the court may take into account in deciding whether to make such an order, it is to take into account--(a) whether the evidence to be adduced in the course of that hearing is likely to be prejudicial to the defendant, and(b) whether the evidence concerned will be adduced in the course of the hearing to decide the preliminary question, and(c) whether the evidence to be adduced in the course of that hearing would be admitted if adduced at another stage of the hearing (other than in another hearing to decide a preliminary question or, in a criminal proceeding, a hearing in relation to sentencing).
(6) Section 128 (10) does not apply to a hearing to decide a preliminary question.
(7) In the application of Chapter 3 to a hearing to determine a preliminary question, the facts in issue are taken to include the fact to which the hearing relates.
(8) If a jury in a proceeding was not present at a hearing to determine a preliminary question, evidence is not to be adduced in the proceeding of evidence given by a witness at the hearing unless--(a) it is inconsistent with other evidence given by the witness in the proceeding, or(b) the witness has died.