In relation to the present case, experience has shown that the attraction of the separate trial of issues is often illusory; it is a course that often causes the very delay, additional expense and uncertainty of outcome it was intended to avoid. It is self-evident that generally a trial on liability alone will be shorter and less costly than a trial on both liability and damages. But it is equally self-evident that separate trials will not necessarily lead to the overall action being resolved sooner or at a lesser cost. If the plaintiff is successful on liability and it is necessary to have a further trial on the issue of damages, the contrary may well be the case. Separate trials also raise the prospect of separate appeals on the findings on liability and quantum, which, if it occurs, will increase the time and expense involved in the overall action. The vagaries of litigation are such that its course often does not run smoothly, or predictably. An application for the separation of issues is therefore to be approached with some caution. See generally Tepko Pty Ltd v Water Board [2001] HCA 19; (2001) 206 CLR 1, 55.
The starting point is that ordinarily the trial of an action should include all issues arising in the action. The determination of an application for separate trials requires a careful balancing of the prospective advantages and disadvantages involved in separating the issues, bearing in mind the uncertainties inherent in litigation, and that, once embarked upon, it is a course from which it may be difficult and even impossible to retreat. It should only be embarked upon where its utility, economy and fairness to the parties is clearly made out: Tepko (55).
It is impossible to provide a comprehensive description of the circumstances in which it is appropriate for there to be separate trials of liability and damages. The exercise of the discretion to make such an order will depend upon what is in the interests of justice in the particular case. However, the separate trial of issues will generally only be appropriate in cases where there is a clear line of demarcation between those issues, and the determination of one in isolation from the other is likely to result in a substantial saving in time, inconvenience and expense : Allen v Gulf Oil Refining Ltd [1980] UKHL 9; [1981] AC 1001; Smith v Maloney (1998) 19 WAR 209 at 223.