"I am not so sure that it is so difficult to draw a line between irregularities, by which I mean defects in procedure which fall within Ord. 70, and true nullities, though I agree no precise definition of either is possible. I think part of the difficulty is that the phrase 'ex debito justitiae' has been taken as being equivalent to a nullity, but, with all respect to Lord Greene's judgment in Craig v Kanssen [1943] 1 KB 256, 258 et seq, it is not. The phrase means that the plaintiff is entitled as a matter of right to have it set aside. Let me quote an analogy. The right to wind up a company is by statute a discretionary right. Yet the books and authorities point out that in many cases as against the company an unpaid creditor on a winding-up petition is entitled to a winding-up order ex debito justitiae. This means no more than that, in accordance with settled practice, the court can only exercise its discretion in one way, namely, by granting the order sought. So in many of the cases where there are defects of procedure, even if the defects are mere irregularities for the purposes of Ord 70 so that the court has a discretion, it must follow that the applicant, if he is in no wise estopped by conduct or waiver, is entitled to say: 'I am entitled under Ord 70 to have the order made upon me set aside ex debito justitiae.'" Indeed the only difference between a nullity and an irregularity, to which such a principle applies, is where being a nullity, it is too late to start again.