No. 27 326 Freedom of Information 2003 (b) would be detrimental to the preservation of the document or, having regard to the physical nature of the document, would not be appropriate; or (c) would involve an infringement of copyright (o'. ier than copyright owned by the Government) subsisting in the document, access in that form may be refused and access given in another form. Deferral of access 21. (1) A public authority which receives a request may defer the provision of access to the document concerned until the happening of a particular event (including the taking of some action required by law or some administrative action), or until the expiration of a specified time, where it is reasonable to do so in the public interest or having regard to normal and proper administrative practices. (2) Where the provision of access to a document is deferred in accordance with subsection (1), the public authority shall, in informing the applicant of the reasons for the decision, indicate, as far as practicable, the period for which the deferment will operate. Refusal of access in certain cases 22. A public authority dealing with a request may refuse to grant access to a document i n accordance with the request, withou,', having caused the processing o f the r equest to have been undertaker., if the public authority i s satisfied t hat the work involved i n proce: sing t he request would substantially and unreasonably interfere with tha normal operations of the public authority, and i f before refusing to provide information on these grounds, the public authority has taken reasonable steps to assist the applicant to reformulate the application so as to avoid causing such interference. Decisions to be made by authorised persons 23. A decision in respect of a request made to a public authority may be made, on behalf of the public authority, by the chief executive officer of the public authority or, subject to the regulations, by an officer of the public authority acting within the scope of authority exercisable by him in accordance with the arrangements approved by the chief executive officer of the public authority. Reasons for decisions t o be given 24. (1) Where in relation to a request for access to a document of a public authority, a decision is made under this Part that the applicant is not entitled to access to the document in accordance with the request