Inherent jurisdiction to set aside order to prevent miscarriage of justice exercised rarely

Horner v. Benisasia, 2013 ONCA 136 deals with the common law power of a superior court to set aside orders to prevent a miscarriage of justice. While holding such power exists the Court is clear such power is to be exercised rarely:

[16]       As to the third basis argued – the court's inherent jurisdiction at common law to set aside or change an order to prevent a miscarriage of justice where new facts have arisen or been discovered – West v. West,2001 CarswellOnt 1936, 18 R.L.F. (5th) 440 relied on by the appellant, notes that a "fairly stringent" test must be met before the court will exercise that jurisdiction.  Without commenting on the applicability of that test in a context such as this, the test includes that the evidence sought to be relied on must not have been in existence or not discoverable by diligent effort by the party asking the court to change the order.  That was clearly not the case.