(3) Subsection (1) does not apply to a document that contains purely statistical, technical or scientific material unless the disclosure of the document would involve the disclosure of any deliberation or decision of Cabinet. (4) For the purposes of this Act, a certificate signed by the Secretary to the Cabinet or a person performing the duties of the Secretary, certifying that a document is one of a kind referred to in a paragraph of subsection (1), establishes conclusively that it is an exempt document of that kind. (5) In this section - Internal working documents and policy documents (a) “Cabinet” includes a committee or subcommittee of Cabinet; and (b) a reference to a document includes a reference to a document whether created before or after the commencement of this Act. 26. (1) A document is an exempt document if it is a document the disclosure of which under this Act would be contrary to the public interest and (a) would disclose matter in the nature of an opinion, advice or recommendation prepared by an officer or a Minister, or consultation or deliberation that has taken place between officers, Ministers, or an officer and a Minister, in the course of, or for the purpose of, the deliberative processes involved in the functions of a public authority; or (b) would prejudice the formulation or development of policy by the Government, by having an adverse effect on (i) the free and frank provision of an opinion, advice or recommendation, or (ii) the free and frank exchange of views for the purposes of deliberation. (2) In the case of a document of the kind referred to in section 22(1), the matter referred to in subsection (1)(a) does not include 21