Defendant contends that his constitutional right to effective assistance of counsel was denied because of the undisclosed conflict of interest existing between defendant and one of his attorneys, Richard Dailey. We agree, and award defendant a new trial.
A defendant is entitled to collaterally attack a judgment entered on his guilty plea, on the grounds that it was not voluntarily and knowingly given. Blackledge v. Allison, 431 U.S. 63, 52 L.Ed. 2d 136, 97 S.Ct. 1621 (1977); G.S. 15A-1420(c); State v. Roberts, 41 N.C. App. 187, 254 S.E. 2d 216 (1979). Where defendant alleges that ineffective assistance of counsel caused him to enter his guilty plea, an issue of constitutional rights arises, and the fact that defendant signed an agreement form does not bar his right to seek post-conviction relief. See State v. Roberts, supra, G.S. 15A-1420; G.S. 15A-1442(5); G.S. 15A-1443(b).
This case raises a question of conflict of interest rendering Dailey’s representation of defendant ineffective; thus, cases discussing competency of representation are not apposite. See *503State v. Hutchins, 303 N.C. 321, 279 S.E. 2d 788 (1981), and cases cited therein. Although we are not aware of previous decisions involving a conflict such as the one under review here, several Supreme Court cases involving claims of ineffective assistance of counsel in the context of an attorney’s multiple representation of co-defendants are instructive.
In Glasser v. U.S., 315 U.S. 60, 86 L.Ed. 680, 62 S.Ct. 457 (1942), the Supreme Court reversed a defendant’s conviction for conspiracy where defendant’s attorney also represented a co-defendant, and the court was aware of a conflict, but refused to appoint another attorney. Defendant Glasser was able to show prejudice, in that his attorney was prevented from seeking to exclude incompetent evidence and from conducting more effective cross-examinations because of his dual representation. The Court stated, however:
To determine the precise degree of prejudice sustained by Glasser ... is at once difficult and unnecessary. The right to have the assistance of counsel is too fundamental and absolute to allow courts to indulge in nice calculations as to the amount of prejudice arising from its denial.
315 U.S. at 75, 76.
Holloway v. Arkansas, 435 U.S. 475, 55 L.Ed. 2d 426, 98 S.Ct. 1173 (1978) also involved multiple representation of co-defendants by one attorney in a single trial. As in Glasser, defendant Holloway’s attorney was court-appointed, and the court knew of a conflict but refused to remedy it. With regard to the need of a defendant to show how he was specifically prejudiced by his counsel’s conflicting interest, the Court stated:
But in a case of joint representation of conflicting interests the evil — it bears repeating — is in what the advocate finds himself compelled to refrain from doing, not only at trial but also as to possible pretrial plea negotiations and in the sentencing process. It may be possible in some cases to identify from the record the prejudice resulting from an attorney’s failure to undertake certain trial tasks, but even with a record of the sentencing hearing available it would [435 US 491] be difficult to judge intelligently the impact of a conflict on the attorney’s representation of a client. And to assess the *504impact of a conflict of interests on the attorney’s options, tactics, and decisions in plea negotiations would be virtually impossible. Thus, an inquiry into a claim of harmless error here would require, unlike most cases, unguided speculation.
In Cuyler v. Sullivan, 446 U.S. 335, 64 L.Ed. 2d 333, 100 S.Ct. 1708 (1980) the Court reviewed Glasser and Holloway, stating:
Glasser established that unconstitutional multiple representation is never harmless error. Once the Court concluded that Glasser’s lawyer had an actual conflict of interest, it refused “to indulge in nice calculations as to the amount of prejudice” attributable to the conflict. The conflict itself demonstrated a denial of the “right to have the effective assistance of counsel.” 315 US, at 76, 86 L Ed 680, 62 S Ct 457. Thus, a defendant who shows that a conflict of interest actually affected the adequacy of his representation need not demonstrate prejudice [446 US 350] in order to obtain relief. See Holloway, supra, at 487-491, 55 L Ed 2d 426, 98 S Ct 1173. But until a defendant shows that his counsel actively represented conflicting interests, he has not established the constitutional predicate for his claim of ineffective assistance. See Glasser, supra, at 72-75, 86 L Ed 680, 62 S Ct 457.
We hold that defendant’s showing that Dailey was under investigation for his own participation in criminal conduct involving defendant, accompanied by Dailey’s knowledge of these circumstances, established a conflict of interest between Dailey and defendant. It is therefore unnecessary for us to speculate as to whether or how much defendant may have been prejudiced by such a conflict. Prejudice in these circumstances must be conclusively presumed.
We hold that because defendant was denied effective assistance of counsel, his plea of guilty was not knowingly and voluntarily made. See Blackledge, supra, Roberts, supra. Defendant is therefore entitled to a
New trial.
Judge Webb concurs. Judge Martin (Robert M.) dissents.