Reasonable apprehension of bias

Lloyd v. Bush, 2012 ONCA 349 has a useful review of the law on reasonable apprehension of bias:

[24]     In Chippewas of Mnjikaning First National v. Ontario (Minister of Native Affairs), 2010 ONCA 47, leave to appeal refused [2010] SCCA No. 91, at para. 229 and Canadian College of Business and Computers Inc. v. Ontario (Private Career Colleges Act, Superintendent), 2010 ONCA 856, at para. 23, this court noted that the well-settled test for establishing a reasonable apprehension of bias was set out in de Grandpré J.'s dissenting judgment in Committee for Justice and Liberty v. Canada (National Energy Board), [1978] 1 S.C.R. 369 at pp. 394-95:
The proper test to be applied in a matter of this type was correctly expressed by the Court of Appeal.  As already seen by the quotation above, the apprehension of bias must be a reasonable one, held by reasonable and right minded persons, applying themselves to the question and obtaining thereon the required information.  In the words of the Court of Appeal, that test is "what would an informed person, viewing the matter realistically and practically – and having thought the matter through – conclude.  Would he think that it is more likely than not that [the decision-maker], whether consciously or unconsciously, would not decide fairly."

...

The grounds for this apprehension must, however, be substantial and I entirely agree with the Federal Court of Appeal which refused to accept the suggestion that the test be related to the "very sensitive or scrupulous conscience".

[25]     There is a strong presumption in favour of the impartiality of a trier of fact: see for example Chippewas, at para. 243, Kelly v. Palazzo (2008), 89 O.R. (3d) 111 (C.A.) at para. 20, leave to appeal refused, [2008] S.C.C.A. No. 152; Peart v. Peel Regional Police Services Board (2006), 217 O.A.C. 269 (C.A.), at para. 39, leave to appeal refused, [2007] S.C.C.A. No. 10; R. v. A.G. (1998), 114 O.A.C. 336 (C.A.), at para. 42, aff'd [2000] 1 S.C.R. 439; R. v. S. (R.D.), [1997] 3 S.C.R. 484, at paras. 32 and 114.
[26]     Determining whether a reasonable apprehension of bias arises requires a highly fact-specific inquiry.  According to Chippewas, at paras. 230:
The test is an objective one.  Thus, the trial record must be assessed in its totality and the interventions complained of must be evaluated cumulatively rather than as isolated occurrences, from the perspective of a reasonable observer throughout the trial.

[27]     In Chippewas, the court warned at para. 243 that "[i]solated expressions of impatience or annoyance by a judge as a result of frustrations ... do not of themselves create unfairness."