Can a codefendant for whom the court has appointed joint counsel prove that he was denied effective assistance of counsel?

It is the rule that a codefendant for whom the court has appointed joint counsel need not establish an actual conflict of interest to show he was denied the effective assistance of counsel; it is sufficient if the record provides an adequate basis for an "informed speculation" that there was a potential conflict of interest which prejudicially affected the [85 Cal.App.3d 520] defendant's right to effective counsel. (See People v. Cook (1975) 13 Cal.3d 663, 670, 119 Cal.Rptr. 500, 532 P.2d 148.) Our "informed speculation" is that both defendants were so prejudiced in this case.