'No such relief [which might affect the exercise of the Convention right to freedom of expression] is to be granted so as to restrain publication before trial unless the court is satisfied that the applicant is likely to establish that publication should not be allowed.'
The courts were freed from this fetter by the decision of your Lordships' House in American Cyanamid Co v Ethicon Ltd[1975] AC 396. Lord Diplock said, at pages 407-408, that the court must be satisfied the claim 'is not frivolous or vexatious; in other words, that there is a serious question to be tried'. But it is no part of the court's function at this stage of litigation to try to resolve conflicts of evidence on affidavit nor to decide difficult questions of law calling for detailed argument and mature consideration. Unless the applicant fails to show he has 'any real prospect of succeeding in his claim for a permanent injunction at the trial', the court should proceed to consider where the balance of convenience lies. As to that, where other factors appear to be evenly balanced 'it is a counsel of prudence' for the court to take 'such measures as are calculated to preserve the status quo'.