11. The assessment of the chance that the prospective witness will be able to give information which will materially assist the defence in its case will depend largely upon the position held by the prospective witness in relation to the events in question, any relationship he may have (or have had) with the accused which is relevant to the charges, the opportunity which he may reasonably be thought to have had to observe those events (or to learn of those events) and any statements made by him to the prosecution or to others in relation to those events.  The test would have to be applied in a reasonably liberal way but, just as in relation to such applications for access to confidential material, the defence will not be permitted to undertake a fishing expedition – where it is unaware whether the particular person has any relevant information, and it seeks to interview that person merely in order to discover whether he has any information which may assist the defence.

17.     Where […] an appellant seeks the issue of a subpoena to a prospective witness to be interviewed in anticipation of tendering that person’s evidence on appeal pursuant to Rule 115, the legitimate forensic purpose to be established must be slightly adapted.  An appellant must establish that there is a reasonable basis for his belief that there is a good chance that the prospective witness will be able to give information which will materially assist him in relation to clearly identified issues arising in his appeal against conviction, that the defence has been unable to obtain the cooperation of the witness, and that it is at least reasonably likely that an order would produce the degree of cooperation needed for the defence to interview the witness.  If those matters are established, then […] the appellant would be entitled to the orders which he seeks pursuant to Rule 54.