(1) The Government has a privilege to refuse to disclose and to prevent any other person from disclosing the identity of a person who has supplied to the Government information purporting to reveal the commission of a crime or a plan to commit a crime.

(2) The Government does not under this section have privilege to refuse to disclose a communication from such a person except to the extent necessary to protect the identity of the person from disclosure.

(3) The Government's privilege under this section may be claimed by any person authorised by the Government to claim the privilege.

(4) The Government has no privilege under this section if the identity of the informant has been disclosed to the public by the Government or the informant or if the informant appears as a witness in court in an action to which his communication relates.

(5) If the Government claims its privilege under this section and the circumstances indicate a reasonable probability that the informant can give testimony necessary to a fair determination of guilt or innocence, in a criminal action the court may on its own motion and shall on the motion of the accused, dismiss the action.