“The administration of justice is a human activity, and accordingly cannot be made immune from error. When a litigant or his adviser makes a mistake, justice requires that he be allowed to put it right even if this causes delay and expense, provided that it can be done without injustice to the other party. The rules provide for misjoinder and non-joinder of parties and for amendment of the pleadings so that mistakes in the formulation of the issues can be corrected. If the mistake is corrected early in the course of the litigation, little harm may be done; the later it is corrected, the greater the delay and the amount of costs which will be wasted. If it is corrected very late, the other party may suffer irremediable prejudice.” Millett LJ in Gale v Superdrug Stores Plc [1996] 1 WLR 1089 at 1098E
