Following a decision against the taxpayer, the trial judge recused himself from considering residual issues (e.g. costs) because of statements made about his judgment and his trial conduct in the taxpayer's factum filed in the Court of Appeal (see s. 247(2).)
The taxpayer moved under Rule 75 to amend its notice of appeal in order to add a new ground of appeal: the trial judge, in responding to the factum in detail, improperly injected himself into the appeal process and compromised its integrity.
Stratas JA allowed the taxpayer's motion. The jurisprudence on Rule 75 deals mainly with trials rather than appeals, but similar principles apply (para. 8):
[T]he Court must understand the nature of the parties' case, assess whether the amendment is relevant to the determination of that case, and, where a new ground of appeal is being asserted, ask whether that ground can possibly succeed.
The motions judge can also refuse amendment if the moving party has been dilatory, or considerations of fairness or prejudice so warrant (para. 10).
The new ground of appeal was novel, and was not obviously lacking merit (para. 11). Fairness reasons also supported the taxpayer's motion (para. 12).