“Where an interim injunction is granted the court will normally reserve the costs of the application until the determination of the substantive issue ( Desquenne …) However, the court's hands are not tied and if special factors are present an order for costs may be made and those costs summarily assessed ( Picnic at Ascot ) …” 36. In our judgment, that short passage accurately represents the law. We were referred by the respondents to cases in which different orders have been made, but we do not consider that those cases undermine the statement of the general rule in the White Book , as decided by the two cases. Meeting a submission by Mr Shepherd that this statement no longer represents the modern practice in the High Court which now required adherence to the “pay as you go” principle, we were also referred by Mr Grant and Mr Munby to a number of cases in which experienced judges had made “costs reserved” orders in interim injunction cases, relying upon the decided cases…. 48. As we have said, we consider that the judge erred here in failing to have proper regard to Desquenne[2001] FSR 1 as authoritative in a case where he was expressly deciding that he could not resolve the underlying disputes between the parties. We find that it was wrong to try to identify a winner or loser in these interim proceedings. We consider that he should have regarded the pragmatic approach adopted by the appellant, both before the application on short notice to Trower J and before the later hearing as very strong grounds on which to reserve the costs. 49. In the light of what we find to be important errors by the learned judge, in the very difficult circumstances before him, it falls to us to exercise our own discretion as to these costs. We are clearly of the view, as Morritt LJ and Morison J were in Desquenne, that the decision here was unjust in all the circumstances. In this hotly disputed case, in which the underlying issues were impossible to determine at the interim stage, it is right to follow the normal rule emerging from Desquenne . We find no special factors indicating a contrary decision. 50. We would add that it is likely to be helpful to parties endeavouring to make sensible arrangements in cases such as this pending trial that they should know that costs are likely to be reserved. We also think that Mr Grant made a telling point for the appellant when he pointed out that the transcript shows that the argument on costs covers between six and seven pages only of 42 pages for the hearing as a whole. On that very short argument, at the end of a difficult hearing, submits Mr Grant, his client potentially became liable to pay over£277,000 in costs. We agree that such a liability needed rather wider consideration than could be given to it on that day and was another pointer towards ordering that the costs be reserved.”