There is an obvious danger in seeking to summarise the considerations which bear upon the granting of leave to appeal. Ultimately what must govern is the justice of the case as it appears to the Court from which leave to appeal is sought, and that means justice to all parties, not just the applicant. As I said at the outset it is not appropriate for us to do any more than lay down guidelines and any guidelines will sometimes be found inadequate; but with that rider, the foregoing might be summarised along the following lines: When leave is sought to appeal under s 148, it will be necessary for the applicant to identify a question of law which is relevant to the granting of the relief sought on appeal. The importance of the question, either generally or to the would-be appellant in a particular case, will probably be relevant. The applicant must show that there is a real or significant argument to be put on that question of law at least to this extent: that there is sufficient doubt about it to justify the grant of leave. Moreover, it may have to be shown that to allow the error to go uncorrected would impose substantial injustice, although, where the order below is final, that injustice will often be more readily discernible.