(1) Except as provided in this section, no witness in any civil or criminal proceedings shall be obliged or permitted to disclose the name or address of any informer or the substance and nature of the information received from him or to state any matter which may lead to his discovery.
(2) If any book, document, record or paper which is in evidence or is liable to inspection in any civil or criminal proceedings contains any entry in which any informer is named or described or which might lead to his discovery, the court shall cause all such entries to be concealed from view or to be obliterated so far only as may be necessary to protect the informer from discovery.
(3) If in a trial for any offence under this Act the court after full inquiry into the case believes that the informer wilfully made in his complaint a material statement which he knew or believed to be false or did not believe to be true, or if in any other proceeding the court is of the opinion that justice cannot be fully done between the parties to the proceeding without the discovery of the informer, it shall be lawful for the court to require the production of the original complaint, if in writing, and permit inquiry and require full disclosure concerning the informer.