However, where a judgment is given in relation to a claim on the group register in relation to one or more of the GLO issues (for example, in respect of a test case), it will be binding on the parties to the other claims on the register at the time the judgment is given, unless the court orders otherwise. Similarly, a judgment made in representative proceedings will be binding on all those represented in the claim, although it may only be enforced by or against a person who is not a party to the claim with the court's permission.
Under the common law the English courts will generally recognise and enforce foreign judgments for a debt or definite sum of money, where the judgment is final and conclusive and the original court had jurisdiction. Various other enforcement regimes may also apply. It is therefore likely that, provided any foreign judgment in a class action meets these criteria, it will also be recognised and enforced. However, the question of whether such a foreign decision will have preclusive effect, and thus prevent class members from attempting to relitigate issues before the English courts, is unclear, particularly in respect of class members that did not take an active role in the foreign litigation but nevertheless did not specifically opt out.