In Ackerman v Thornhill QC [2017] EWHC 99, the English High Court considered when a judgment can be set aside by way of res judicata.

In 2011, Mr Joseph Ackerman brought an action against the defendants, challenging a number of transactions that related to the demerger of property owned in a family group.  The Judge dismissed the claim.  The parties signed a consent order before any appeal was heard.  In that order, they agreed that the appeal should be dismissed, and that Mr Ackerman would not continue to pursue the proceedings.

In 2015, Mr Ackerman brought a further claim against the defendants.  The defendants applied to strike out the claim on the basis that either the doctrine of res judicata (ie the matter in dispute had already been decided by a competent court), or that the terms of the settlement in the consent order barred Joseph from pursuing the 2015 claim.  Mr Ackerman sought to amend the pleading to apply to set aside the 2011 judgment, claiming the defendants obtained the 2011 judgment by fraud, collusion and dishonesty. 

The defendants' strike-out application was granted.  On the facts, the Court considered there was no prospect of Mr Ackerman succeeding in his fraud allegation. 

In reaching this conclusion, the Court applied the House of Lords' approach in Hunter v Chief Constable of the West Midlands Police [1982] AC 529, which set out when a judgment could be set aside.  In particular, there needs to be:

  • Fresh evidence that was not available, or which could not with reasonable diligence have been obtained, at the time of the judgment in the earlier claim
  • 'Conscious and deliberate dishonesty' in relation to the concealment of that evidence
  • Material evidence, ie that such evidence would have entirely changed how the judge decided that earlier claim.

See the Court's decision here.