I was coming to that very point. Interventions can prove difficult for the courts to control. The reason I say that is because on occasions an application is made for an intervener to intervene
and, on the face of it, the judge deciding whether or not they can intervene will do so on the basis that they have a knowledge of the case. The judge, having regard to the submissions that he or she receives, considers that the intervener might well be of assistance. The level and degree of intervention is then very often beyond the control of the judge who originally gave permission, so that one can then encounter—perhaps at the hearing of a judicial review, or at the Court of Appeal stage—a very substantial skeleton argument, bundles of authorities, and arguments which range very loosely around the subject matter of the dispute. Here I speak from experience.
Inevitably, this causes expense to all parties involved, whether the applicant or the respondent, because they have to consider the arguments. They cannot rest assured that the judge is simply going to ignore everything on the basis that it might be outside the scope of the intervention. Of course, good judges customarily curtail submissions made orally once the matter gets to the stage of a hearing, and do so effectively. That does not remove the danger of quite excessive levels of intervention and contribution.