What is the effect of a failure to obtain leave to serve a notice to continue an injunction before appearance?

This, in my opinion, is not a case where the plaintiff should have relief under the Rule. I would not want to encourage the careless practice which this record shows. It bristles with irregularities. There ought to be some regard for the Rules of practice. This too is a case where the liberty of the subject is at issue, and where the Rules of procedure should be strictly complied with. As to the failure to obtain leave to serve the notice to continue the injunction before appearance, that is more than a mere non-compliance with the Rules. The decisions, in my opinion, establish that leave is essential not merely to the regularity, but also to the validity of the notice. Without leave first having been obtained it was “unwarranted by any enactment or rule,” and therefore “much more than an irregularity.” Smurthwaite v. Hannay [1894] A.C. 494, at p. 501, 63 L.J.Q.B. 737, per Lord Herschell, L.C.