Striking Pleadings - Leave to Amend. Asghar v. Toronto Police Services Board
In Asghar v. Toronto Police Services Board (Ont CA, 2019) the Court of Appeal commented on the granting of leave to amend after a R21 motion:
 The usual result when a pleading is struck is to grant leave to amend. The principles are set out in Spar Roofing & Metal Supplies Ltd. v. Glynn, 2016 ONCA 296, 348 O.A.C. 330, at paras. 35-45, where Weiler J.A. pointed out that this approach is consistent with the generous approach to pleadings amendment under r. 26. Leave to amend should accordingly be denied only in the clearest of cases: South Holly Holdings Ltd. v. The Toronto-Dominion Bank, 2007 ONCA 456, at para. 6; and Tran v. University of Western Ontario, 2015 ONCA 295, at para. 26.. TSI International Group Inc. v. Formosa
In TSI International Group Inc. v. Formosa (Ont CA, 2017) the Court of Appeal makes clear that, absent a clear basis for denying it, leave to amend struck pleadings should be granted if requested:
 We are able to dispose of this appeal without addressing the substantive grounds of appeal raised. The motion judge ought to have granted leave to amend after striking from the appellants’ statement of defence and counterclaim the defence of “clean hands” and the counterclaim of “abuse of process”, and a number of paragraphs. Leave to amend should be denied only in the clearest of cases. The motion judge did not explicitly explain why he refused leave to amend. We are not persuaded by respondent’s counsel’s submission that the explanation is apparent from reading the reasons as a whole.. Conway v. The Law Society of Upper Canada
 As in Tran v. University of Western Ontario, 2015 ONCA 295 (CanLII), we conclude that in the absence of any articulated basis on which leave was denied and in the absence of any prior amendment, the appellants should not be deprived of the opportunity to amend their pleadings.
In Conway v. The Law Society of Upper Canada (Ont CA, 2016) the Court of Appeal generally stated the principles applicable to granting leave to amend a claim that has been struck down on a motion striking pleadings:
ii. Whether leave to amend the statement of claim should have been granted:
 The appellant argues that the motion judge erred in determining that the appellant should not be granted leave to amend his pleading because of the motion judge’s conclusion that there was no actionable tort possible on the facts as alleged in the statement of claim.
 The decision not to grant leave to amend should only be made in the clearest of cases, when it is plain and obvious that no tenable cause of action is possible on the facts as alleged: South Holly Holdings Ltd. v. The Toronto-Dominion Bank, 2007 ONCA 456 (CanLII), at para. 6. That said, the decision whether or not to grant leave to amend a pleading is a discretionary one, and absent palpable and overriding error of fact or error of law, such a decision is subject to deference on appeal: Mortazavi v. University of Toronto, 2013 ONCA 655 (CanLII), at para. 3.