Issue estoppel is a principle of law which prevents re-litigation of disputes before Courts. It applies to facts directly decided by English Courts, and those matters which form part of the decision which were necessary to making the finding of fact or law. When a judgment of a court is final and conclusive, it decides the issues in dispute before it once and for all, and cannot be disputed by the same parties again before the same or another court in the event that issue estoppel applies. Issues decided forming the groundwork of those points, although not directly decided, are also caught by issue estoppel provided those points are necessary and fundamental to the judgment.
When Issue Estoppel Applies
Application of the principle differs from cause of action estoppel in the following respects:
- Issue estoppel relates to a particular issue, rather than the entire set of facts which is the subject of cause of action estoppel;
- An issue may be determined at an interim stage of the previous proceedings on a part of the dispute, such as a jurisdictional or procedural issue;
- The subject matter of an estoppel is a subset of what might be relevant in cause of action estoppel. As such, issue estoppel focuses on specific issues of fact or law rather than all the material facts. With cause of action estoppel, the parties are entitled to traverse in the litigants' pleadings to ascertain relevant facts which were decided;
- Issue estoppel may apply to different causes of action – so where cause of action estoppel may not be successful, issue estoppel may be. This is because issue estoppel focuses on specific findings of fact or law.
The previous adjudication of the court, regardless of its form, must be a res judicata and as such a final and conclusive judgment (a decision which finally determines the dispute on the merits of the case). It also be raised as a defense on the final judgment of the previous court in subsequent litigation.
Application to Foreign Judgments
For the purposes of private international law, foreign judgments are just as effective to base a defense. The requirements to make out an estoppel on this ground raised from a foreign judgment are:
- The previous judgment must be derived from a court of competent jurisdiction;
- The foreign judgment must be res judicata within the meaning of the lex fori (ie in that the foreign judgment is final and conclusive from the perspective of the foreign court);
- The foreign judgment must of a res judicata within the meaning of English private international law;
- The issue in question raised in the subsequent English proceedings must be the same as that decided in the foreign proceedings, and must have been necessary and fundamental to the decision in the foreign court and not merely collateral. The issue in question need not be one that disposes of the substantive claim;
- The parties to the previous litigation must be the same, or privies of those participating in the previous dispute.
In respect to foreign decisions, English Courts will have regard to the pleadings, the judgment, the reasons for judgment (if any), the evidence presented to the adjudicating court and matters of procedure in the foreign court to verify that the issue in question has previously been judged. This is part of the process which an English Court adopts to exercise special caution in respect to foreign judgments.
Issue estoppel applies in situations where Courts have previously decided disputes, and prevents re-litigation of disputes. These principles of law exist as a matter of public policy so that disputing parties are preventing from re-raising the same disputes again, so that finality is brought to the existence of disputes.