An appeal to the Full Bench lies only by leave of a Full Bench: s.120(1). A Full Bench must grant leave to appeal if, in its opinion, the matter is of such importance that, in the public interest, leave should be granted: s.120(2). Otherwise, a grant of leave is governed by the conventional considerations for the grant of leave to appeal by an appellate court which include whether the decision is attended with sufficient doubt to warrant its reconsideration or whether substantial injustice may result if leave is refused. However, "[t]hese 'grounds' should not be seen as fetters upon the broad discretion conferred by [s.120(1)], but as examples of circumstances which will usually be treated as justifying the grant of leave" although "[i]t will rarely, if ever, be appropriate to grant leave unless an arguable case of appealable error is demonstrated. This is so simply because an appeal cannot succeed in the absence of appealable error". [3]