What is the case law on res judicata and abuse of process?

Madam Justice Arbour gave judgment for the majority in both decisions. In Toronto v. C.U.P.E., at ¶15, she neatly summed the issue: … The body of law dealing with the relitigation of issues finally decided in previous judicial proceedings is not only complex, it is also at the heart of the administration of justice. Properly understood and applied, the doctrines of res judicata and abuse of process govern the interplay between different judicial decision makers. These rules and principles call for a judicial balance between finality, fairness, efficiency and authority of judicial decisions.

The common law doctrines of issue estoppel, abuse of process and collateral attack are interrelated with more than one doctrine supporting a particular outcome. Issue estoppel and collateral attack are capable of being viewed as particularly applications of the broader doctrine of abuse of process. [Toronto v. C.U.P.E., ¶15, ¶22]

If the plaintiff’s action implicitly and necessarily attacks the correctness of Macaulay J.’s order it is a prohibited collateral attack. As noted by Arbour J. in Toronto v. C.U.P.E., at ¶34: … It is an implicit attack on the correctness of the factual basis of the decision, not a contest about whether that decision has legal force, as clearly it does. Prohibited "collateral attacks" are abuses of the court's process. However, in light of the focus of the collateral attack rule on attacking the order itself and its legal effect, I believe that the better approach here is to go directly to the doctrine of abuse of process.

The University argues that the plaintiff’s Further Amended Statement of Claim rests on factual assertions which are inconsistent with the Order of Mr. Justice Macaulay. The case of Hunter v. Chief Constable of West Midlands Police, [1982] A.C. 529, [1981] 3 All E.R. 727, well illustrates the existence of collateral attack where a feature presently advanced in a civil proceeding could not exist consistently with a prior finding in a criminal proceeding.