When a party is barred from raising in later proceedings a matter decided, or capable of having been decided, in earlier ones. Virgin Atlantic Airways Ltd v Zodiac Seats UK Ltd; Divine-Bortey v Brent London Borough Council; Sajid v Sussex Muslim Society.
Res judicata; Henderson v Henderson abuse; second ET claim. A race discrimination claim founded on evidence that emerged mid-hearing of an earlier unfair dismissal complaint (the 'African accent' remark) was barred: the Henderson v Henderson rule applies with full force in the employment tribunal, and the factors relied on by the EAT — lay representation, the point emerging without warning, no prompt from the tribunal — did not amount to special circumstances. The rule exists to avoid multiplicity of litigation, with its wasted cost, duplication of effort, dispersal of evidence and risk of inconsistent findings (Potter LJ at 898).
Res judicata; cause of action estoppel; withdrawal to pursue High Court claim. Where a claimant withdraws an ET breach of contract claim having expressly reserved the right to pursue the same claim in the High Court because of the £25,000 jurisdictional cap, the tribunal's dismissal on withdrawal does not create a cause of action estoppel: the order was never intended as a final determination on the merits, and barring the civil claim would offend the principle of justice underlying res judicata rather than serve it. Distinguishes Barber v Staffordshire County Council, where the claim was abandoned outright with no intention to litigate elsewhere.
Res judicata; taxonomy. Lord Sumption's authoritative restatement (paras 17-26): 'res judicata' is a portmanteau term covering five distinct principles — cause of action estoppel (absolute as to points actually decided), merger in judgment, issue estoppel (capable of exception where new material emerges), the Henderson v Henderson rule against raising points that could and should have been raised earlier, and the broader doctrine of abuse of process. The standard starting point for any relitigation argument, in the ET as elsewhere.