Many have said that the leading case on the mitigation obligation in an employment context is the 2008 Supreme Court of Canada decision in Evans v Teamsters Local 180. In reality, it added only one new wrinkle. The fundamental principles of mitigation were in place years before this decision and repeated once again.

It did deal, however, with the new concept of considering the obligation of a dismissed employee to return to work at the request of the employer for the notice period, following a termination. This was really the only new principle and in dealing with this, it repeated Mifsud concepts.

One issue raised by the appellant was that this case was to be distinguished from the line of cases dealing with constructive dismissal arguments and the consequential argument of mitigation which has arisen in that context. On this point, the majority agreed with the B.C. Court of Appeal in Cox which and concluded that there was no conceptual distinction to be drawn between the two circumstances, although each situation should be reviewed on its own facts:

[28] In my view, the courts have correctly determined that in some circumstances it will be necessary for a dismissed employee to mitigate his or her damages by returning to work for the same employer.  Assuming there are no barriers to re-employment (potential barriers to be discussed below), requiring an employee to mitigate by taking temporary work with the dismissing employer is consistent with the notion that damages are meant to compensate for lack of notice, and not to penalize the employer for the dismissal itself.  The notice period is meant to provide employees with sufficient opportunity to seek new employment and arrange their personal affairs, and employers who provide sufficient working notice are not required to pay an employee just because they have chosen to terminate the contract.  Where notice is not given, the employer is required to pay damages in lieu of notice, but that requirement is subject to the employee making a reasonable effort to mitigate the damages by seeking an alternate source of income.

The Supreme Court referred back to the Ontario Court of Appeal decision in 1989, Mifsud v MacMillan Bathurst in which the Court spoke of the duty of the demoted employee to remain in the employ of the party in default “where the salary offered is the same, where the working conditions are not substantially different or the work demeaning, and where the personal relationships are not acrimonious”.

The decision of the Supreme Court, however, determined that the test for mitigation on the facts as in Evans, that is, return to the employ of that person who was just terminated for the notice period, and Mifsud, which is, remain employed with the party who committed the fundamental breach, is one and the same.

For this reason, the case law assessing the Mifsud principle, one often denied in its application as refused presently, may be also used in reviewing the Evans defence.