—(1) Except as provided in subsection (3), no witness in any civil or criminal proceedings shall be obliged —
to disclose the name and address of any informer who has given information with respect to an offence under this Act; or
to answer any question if the answer thereto would lead, or would tend to lead, to the discovery of the name or address of any informer.
(2) If any book, document or paper which is in evidence or liable to inspection in any civil or criminal proceedings contains any entry in which any informer is named or described or which may lead to his discovery, the court shall cause those entries to be concealed from view or to be obliterated so far as may be necessary to protect the informer from discovery.
(3) If —
in any proceedings before a court for an offence under this Act, the court, after full inquiry into the case, is satisfied that an informer wilfully made a material statement which he knew or believed to be false or did not believe to be true; or
in any other proceedings, the court is of the opinion that justice cannot be fully done between the parties thereto without the disclosure of the name of an informer,
the court may permit inquiry and require full disclosure concerning the informer.
[Misuse of Drugs Act, s. 23]