What is the proper standard of review for reviewing the findings of a Commissioner of Inquiry?

The circumstances of this application point unequivocally in the direction of reasonableness as the proper standard to use in reviewing the Commissioner’s findings. The nature of the issue here – findings of fact – clearly indicates that the Commissioner’s work should be shown a significant amount of deference. He had the great advantage of seeing and hearing the testimony first hand and many of his central findings are rooted in assessments of credibility. Just as an appeal court should not lightly interfere with the findings of fact made by a trial judge, so a court acting in relation to a judicial review application should not lightly interfere with the findings of a commission of inquiry. See: Housen v. Nikolaisen, 2002 SCC 33, [2002] 2 S.C.R. 235.