In 2008, Harvey, an experienced businessman, guaranteed a debt owed to Dunbar Assets plc (Dunbar).  Dunbar subsequently served a statutory demand on Harvey in 2011 for payment under the guarantee.

In 2012, Harvey applied, unsuccessfully, to set aside the demand in the County Court on the ground of promissory estoppel.  However, the demand was subsequently set aside by the Court of Appeal on a completely unrelated ground.

Dunbar issued a second statutory demand in 2014 and, again, Harvey sought to set aside the demand on the ground of promissory estoppel.  Both the County Court and the High Court dismissed the application.  Harvey appealed to the Court of Appeal.

The Court of Appeal concluded that no res judicata or issue estoppel arose from the County Court's judgment in 2012 because the decision was set aside on appeal.  However, the County Court's judgment could still be taken into account in deciding whether the current proceeding was an abuse of process.

It would be an abuse of process, the Court said, if Harvey were permitted to re-argue the promissory estoppel point.  First, he had chosen not to pursue the point beyond its determination at first instance and, secondly, no special or exceptional circumstances existed to justify re-opening the point.  Even if it were not an abuse of process, the Court considered that Harvey's promissory estoppel argument would fail as it was inherently implausible.  The appeal was dismissed.  

See the English Court of Appeal's decision here.