What is the effect of a motion brought by a former solicitor general seeking to overturn a judgment in an action in which he was not a party?

The assessment of Middleton, J.A., in the context of the present motion should read in tandem with the statement of Lord Denning in Abuakwa v. Adanse, [1957] 3 All E.R. 559, at page 561: “The general rule of law undoubtedly is that no person is to be adversely affected by a judgment in an action to which he was not a party, because of the injustice of deciding an issue against him in his absence; but this general rule admits of two exceptions. One exception is that a person who is in privity with the parties, a “privy” as he is called, is bound equally with the parties, in which case he is estopped by res judicata; the other is that a person may have so acted as to preclude himself from challenging the judgment, in which case he is estopped by his conduct . . . ”