reference to the stage when a prayer is made for the production. If any document is necessary or desirable for the defence of the accused, the question of invoking Section 91 at the initial stage of framing of a charge would not arise since defence of the accused is not relevant at that stage . When the section refers to investigation, inquiry, trial or other proceedings, it is to be borne in mind that under the section a police officer may move the court for summoning and production of a document as may be necessary at any of the stages mentioned in the section. Insofar as the accused is concerned, his entitlement to seek order under Section 91 would ordinarily not come till the stage of defence. When the section talks of the document being necessary and desirable, it is implicit that necessity and desirability is to be examined considering the stage when such a prayer for summoning and production is made and the party who makes it, whether police or accused. If under Section 227, what is necessary and relevant is only the record produced in terms of Section 173 of the Code, the accused cannot at that stage invoke Section 91 to seek production of any document to show his innocence. Under Section 91 summons for production of document can be issued by court and under a written order an officer in charge of a police station can also direct production thereof. Section 91 does not confer any right on the accused to produce document in his possession to prove his defence. Section 91 presupposes that when the document is not produced process may be initiated to compel production thereof. ” [Emphasis is ours]