not be incontrovertible. Moreover, where it is "necessary to do so in order to avoid real injustice", in "exceptional" circumstances, and where "there is no alternative effective remedy", CPR 52.17(1) permits both the High Court and the Court of Appeal to re-open a final determination of an appeal. In criminal proceedings, the Court of Appeal also has a discretion to admit fresh evidence on appeal. If it does so, the Court must ask itself whether, in light of the fresh evidence, the conviction is unsafe. Special case of fraud Soon after the passage of the Judicature Acts, it was thought that, when a judgment had been obtained by wilful fraud of the victorious party, the aggrieved party's proper recourse was to bring a new action for fraud, because to try the alleged fraud required original jurisdiction, which the Court of Appeal did not have. In so ruling, Jessell MR made specific references to the supplemental bill of review, the equitable equivalent of the writ of error contra nobis. However, the Court drew an analogy with the old law, rather than preserving it: in agreeing with Jessell MR, James LJ observed, "if it is true that there was a fraud practised upon the Court, by which the Court was induced to make a wrong decree, the way to obtain relief will be to bring a fresh action to set aside the decree on the ground of fraud" [emphasis added]. Since the coming into force of the Civil Procedure Rules, the law has evolved further. In Noble v Owens, the Court of Appeal held that the modern position is that it is now not necessary to commence a fresh action to cure a judgment fraudulently obtained. Instead, the powers of the Court of Appeal under CPR 52.10 are sufficiently broad to permit the Court of Appeal to refer the determination of the issue of fraud to a Judge of the High Court as part of the appeal proceedings, with a consequent saving of costs. In criminal cases, the Court of Appeal has allowed appeals and quashed convictions on the basis of misconduct by Crown witnesses analogous to fraud, e.g., where prosecution witnesses had subsequently been convicted for giving perjured evidence during the original trial; or where police officers who took confessions from the appellants had subsequently been discredited in later proceedings. Recent attempts to resurrect the procedure In Cinpres Gas Injection Ltd