15 Other authorities of similar weight to the group to which I have referred refer to three guidelines, the third being that the plaintiff must prove that damages are not an adequate remedy: eg see Australian Broadcasting Corporation v O'Neill (above) at [19] per Gleeson CJ and Crennan J; Castlemaine Tooheys Ltd v The State of South Australia (1986) 161 CLR 148 at 153 (Mason ACJ); The Mayo Group International Pty Ltd v Hudson Respiratory Care Inc [2005] NSWSC 445 at [25] (Young CJ in Eq); and Tampalini v Robinson [2005] WASC 182 at [3] (Jenkins J). The difference in approach can be seen in recent judgments of the High Court in Australian Broadcasting Corporation v O'Neill (above). Gummow and Hayne JJ adopted the two guidelines approach at [65]:
The relevant principles in Australia [in relation to interlocutory injunctions] are those explained in Beecham Group Ltd v Bristol Laboratories Pty Ltd … This Court (Kitto, Taylor, Menzies and Owen JJ) said that on such applications the court addresses itself to two main inquiries and continued:
The first is whether the plaintiff has made out a prima facie case, in the sense that if the evidence remains as it is there is a probability that at the trial of the action the plaintiff will be held entitled to relief… the second inquiry is… whether the inconvenience or injury which the plaintiff would be likely to suffer if an injunction were refused outweighs or is outweighed by the injury which the defendant would suffer if an injunction were granted.
By using the phrase " prima facie case ", their Honours did not mean that the plaintiff must show that it is more probable than not that at trial the plaintiff will succeed; it is sufficient that the plaintiff show a sufficient likelihood of success to justify in the circumstances the preservation of the status quo pending the trial. That this was the sense in which the Court was referring to the notion of a prima facie case is apparent from an observation to that effect made by Kitto J in the course of argument… With reference to the first inquiry, the Court continued, in a statement of central importance for this appeal:
How strong the probability needs to be depends, no doubt, upon the nature of the rights [the plaintiff] asserts and the practical consequences likely to flow from the order he seeks.
Gleeson CJ and Crennan J adopted the three guidelines approach at [19]:
… In all applications for an interlocutory injunction, a court will ask whether the plaintiff has shown that there is a serious question to be tried as to the plaintiff's entitlement to relief, has shown that the plaintiff is likely to suffer injury for which damages will not be an adequate remedy, and has shown that the balance of convenience favours the granting of an injunction. These are the organising principles, to be applied having regard to the nature and circumstances of the case, under which issues of justice and convenience are addressed. We agree with the explanation of these organising principles and the reasons of Gummow and Hayne JJ and their reiteration that the doctrine of the Court established in Beecham Group Ltd v Bristol Laboratories Pty Ltd should be followed.