21. The principles may be summarised as follows:
1. Time limits are important and must, prima facie, be obeyed.
2. In order to justify a court acceding to an application to extend time, there must be some material on which the court can exercise its discretion.
3. Such an application should only be granted if, having regard to the important value of finality in litigation and the need for time limits to be respected, it is proper to do so.
4. There should be an explanation for the delay, as to which any action (other than to appeal) that has been taken by the applicant is relevant.
5. The court must consider any prejudice to the respondent in defending the proceeding, as caused by the delay, and any such prejudice will tell against the extension.
6. The mere absence of prejudice is not enough to justify the extension of time.
7. The merits of the appeal itself must be taken into account in deciding whether an extension of time should be granted.
8. The court, on considering an application for an extension of time within which to appeal, should not decide the appeal and, in an appropriate circumstance, an arguable case may be sufficient, though in the case of long delay it may be necessary to show that the applicant has a strong case.
9. Nevertheless, the application is to be determined by the court's view of the demands of justice in accordance with a broad judicial discretion and not by the mere application of a verbal formula.
10. In particular, the court will look, above all else, to determine whether there has not been and will not be, if the application is refused, a miscarriage of justice which will always be an overriding consideration.
22. While the terms used are not identical, this is similar to the summary of principles set out by the Full Court of the Supreme Court in Director of Public Prosecutions for the Australian Capital Territory v The Honourable Acting Justice Brian Martin [2014] ACTSC 104 at [159]. Two considerations there expressly mentioned, but not, perhaps, clearly included in my summary above, are the length of the delay and whether the interests of third parties are affected.
23. As the court there noted, one must bear in mind the caution expressed by Burchett J in Pozniak v Minister for Health (1986) 9 ALN N256 that these considerations are "signposts to guide the court's discretion" not "fences to limit the breadth of the field".