Opinion by

On the afternoon of January 31, 1967, appellant, a 19 year old youth, after having learned from friends that he was wanted by the police, voluntarily surrendered to the Scranton Police Department. Appellant’s action was motivated by the fact that he had been earlier advised that one Frank Smith, Jr., had been arrested for a series of burglaries, and had, shortly after being taken into custody, implicated appellant in the commission of these crimes. The following day (February 1, 1967) after having been detained and interrogated for over 21 hours, appellant signed a statement admitting his complicity in seven burglaries. Immediately thereafter, appellant was preliminarily arraigned.

On August 11, 1967, appellant pleaded guilty to one count of burglary (No. 20B), and was sentenced to 18 months imprisonment. On October 2, 1967, appellant proceeded to trial, before a jury, on the second burglary count (No. 7e), and was adjudged guilty. Prior to this trial, a timely filed motion to suppress the confession was denied. (At trial, this challenged confession was, over objection, introduced against appellant). Post-trial motions were denied, and appellant was sentenced to serve a term of 23 months imprisonment. On November 1, 1968, appellant pleaded guilty to the five remaining burglary charges then outstanding against bim (Nos. 7a, b, c, d, and 10). Appellant was sentenced on each of these offenses to serve a term of imprisonment of one and one-half to four years, each sentence to run concurrently with those already being served.

An appeal, allowed as if timely filed, was taken to the Superior Court, which affirmed in an opinionless per curiam order, with two judges dissenting. (Hoffman, J., filed a dissenting opinion, joined by Spaulding, *82J.). This Court granted allocatur, and we now reverse the conviction in No. 7e, and remand for an evidentiaryhearing in Nos. 7a, b, c, d, 10, and 20B.

Appellant here argues, as he did in the Superior Court, that the 24 hour “unnecessary delay” between his arrest and arraignment renders his confession, given only at the end of this period, inadmissible.1 Pa. R. *83Crim. P. 116(a) (effective January 1, 1965, replaced by Pa. R. Crim. P. 118 (effective May 1, 1970)); Commonwealth v. Dutton, 453 Pa. 547, 307 A.2d 238 (1973); Commonwealth v. Tingle, 451 Pa. 241, 301 A.2d 701 (1973); Commonwealth v. Futch, 447 Pa. 389, 290 A.2d 417 (1972). Appellant also contends that the hearing court’s erroneous refusal to suppress the confession was the primary motivation for appellant’s subsequent pleas of guilty to the remaining charges.2 Accordingly, appellant challenges the validity of these pleas. Cf. Commonwealth v. Walters, 431 Pa. 74, 244 A.2d 757 (1968); Commonwealth v. Stokes, 426 Pa. 265, 232 A.2d 193 (1967).

It is now well settled that at the time of appellant’s arrest (1967), all persons “arrested with or without a warrant” were required to “be taken without unnecessary delay before the proper issuing authority for a preliminary arraignment.” Pa. R. Crim. P. 116(a) (effective January 1, 1965) ; Dutton, supra. Where this mandate has gone unfulfilled by the Commonwealth, “all evidence obtained during ‘unnecessary delay’ except that which . . . has no reasonable relationship to the delay whatsoever” must be excluded.3 Futch, supra *84at 394, 290 A.2d at 419 (emphasis added). See Dutton, supra; Tingle, supra. Our task on appeal, therefore, is to determine whether there was an “unnecessary delay,” and if so, whether the evidence obtained is causally related to the delay. Our review of the instant record convinces us that both questions must be answered in the affirmative.

Here, the Commonwealth’s own evidence, as well as the opinion of the trial court, indicates that appellant voluntarily surrendered himself to the Scranton police on the afternoon (approximately 3:00 P.M.) of January 31, 1967. Appellant was thereafter detained and interrogated for 24 hours, and at 3:00 P.M. on February 1, 1967, finally signed a statement admitting his complicity in seven separate burglaries. During this 24 hour period, appellant was returned to his home, in the custody of the police, where evidence (cash receipts) of one crime was obtained by the authorities.

The Commonwealth does not in any way seek to justify this delay, but rather asserts that as appellant was not “threatened” or “abused,” his confession represents a knowing and voluntary, and therefore valid, act. However, this argument misses the point—Pa. R. Crim. P. 116(a) (as well as its progeny Pa. R. Crim. P. 118 and 116) requires that all arrestees be preliminarly arraigned “without unnecessary delay.” The Commonwealth has made no suggestion whatsoever that the instant delay was necessary.4 Accordingly, we must conclude that the 24 hour delay between appellant’s arrest *85and arraignment was “unnecessary,” and hence violative of Rule 116(a). Dutton, supra; Tingle, supra; Futch, supra.

Nor can it be seriously suggested that the challenged confession was not “reasonably related” to this “unnecessary delay.” Futch, supra at 394-96, 290 A.2d at 419. By the Commonwealth’s own concession, appellant, a 19 year-old youth with no prior police contact, did not “confess” until 24 hours after arrest and repeated interrogation.5 It was only then, after giving a written statement, that appellant was preliminarily arraigned. On these facts, “[w]e must conclude that the challenged statement here, as the evidence in Futch, supra, was ‘reasonably related’ to the ‘unnecessary delay’ and thus inadmissible.” Tingle, supra at 247, 301 A.2d at 704.

*86Having determined appellant’s confession to be invalid, and erroneously admitted at his trial, we are now called upon to pass on appellant’s contention that his guilty pleas to the six remaining burglary charges were primarily motivated by the illegally obtained confession. However, the record before us is insufficient to make such a determination. Accordingly, as no post-trial motions were filed by appellant prior to this appeal allowed as if timely filed, the record is remanded to the trial court for the filing of post-trial motions, with instructions, to the trial court, to conduct an evidentiary hearing. Cf. Commonwealth v. Starr, 450 Pa. 485, 301 A.2d 592 (1973); Commonwealth v. Kelly, 436 Pa. 21, 258 A.2d 325 (1969).

The judgment of sentence in No. 7e is reversed and a new trial granted. The records in Nos. 7a, 7b, 7c, 7d, 10, and 20B are remanded to the trial court for the filing of post-trial motions, with instructions to hold an appropriate evidentiary hearing.

Dissenting Opinion by

Two basic errors in today’s decision compel my dissent. First, in entertaining petitioner’s claim that his confession is inadmissible under Futch and Dutton, the majority departs from the rules governing issues presentable on appeals nunc pro tuno which we laid down in Commonwealth v. Faison, 437 Pa. 432, 264 A. 2d 394 (1970). Second, in holding that guilty pleas which follow an inadmissible confession will be invalidated if they were primarily motivated by the confession, the Court appears to overrule, sub silentio, without benefit of briefs or argument on the question, a large part of our still recent decision in Commonwealth v. Marsh, 440 Pa. 590, 271 A. 2d 481 (1970). I believe the trial court was correct and that its judgments of sentence should be affirmed without a remand.

*87I.

In Commonwealth v. Futch, 447 Pa. 389, 290 A. 2d 417 (1972), we promulgated a rule excluding from evidence confessions extracted during and causally related to a period of unnecessary delay prior to arraignment. Since tbe filing of briefs in the present case, Futch has been made retroactive (over my dissenting opinion joined by Chief Justice Jones and Mr. Justice Eagen) to January 1, 1965, the effective date of former Pennsylvania Rule of Criminal Procedure 116(a). Commonwealth v. Dutton, 453 Pa. 547 (1973). This rule, requiring prompt arraignment of all persons arrested, was in effect at the time of appellant’s arrest and confession. However, it does not follow that he may avail himself of the Futch exclusionary rule on this appeal nunc pro tunc.

In Commonwealth v. Faison, supra, we held that an appellant whose appeal is taken nunc pro tunc can raise only those issues properly preserved at trial, and those issues involving alleged deprivations of constitutional rights subsequently announced but retroactively applied. Wayman did not preserve an “unnecessary delay” issue at trial; indeed, he never once mentioned it.1 As to the second category of issues, while it is *88true that Futch is a subsequently announced, retroactively applied rule, it is not a constitutionally based rule. Rather, it was promulgated in the exercise of our supervisory powers, paralleling the McNabb-Mallory rule in the federal courts.2

The reason that subsequently announced but retroactively applied constitutional rights are available on a direct appeal nunc pro tunc is that such issues can be made the subject of a PCHA petition, and it is inefficient to require two proceedings where one would suffice. PCHA proceedings, however, are limited to issues of constitutional dimension,3 and Futch would therefore be unavailable to a PCHA petitioner.4 It follows *89that it is equally unavailable to an appellant proceeding nunc pro time and who did not timely preserve the issue below. I note that the McNabb-Mallory rule is unavailable for precisely that reason on federal collateral attack on a federal conviction.5

Even were we to extend the scope of PCHA relief to “fundamental” trial errors not of constitutional dimension, appellant should not prevail, for violation of the Futch exclusionary rule is clearly not “fundamental” error. The Futch rule is prophylactic, not remedial. It is designed to ensure that in future all prisoners will be promptly arraigned after arrest. Where a confession is shown to have been coerced, the rule is superfluous. It comes into play in precisely those situations where the confession is voluntary and otherwise free from unconstitutional taint. Thus the admission at trial of a confession in all respects valid but obtained during a period of unnecessary delay detracts not a whit from the fairness of the trial proceedings. Indeed, since the deterrent function of the Futch rule will hardly be advanced by its application to facts occurring five years before its announcement, there is no jurisprudential purpose to be served by extending the benefit of the rule to Wayman, much less any fundamental error in admitting Ms confession.

*90In sum, the necessity for judicial finality which is wisely recognized in the Post Conviction Hearing Act also applies to appeals mmc pro time, subject to the exceptions noted in Commonwealth v. Faison, supra. I see no justification for the Court to ignore that salutary formulation of appellate justiciability.

II.

Even assuming that the majority is correct in reaching the merits of Wayman’s Futeh claim, he is in my judgment entitled to no relief.

The first burglary charge brought against Wayman (No. 20B) was for a crime not touched upon in his confession and at the scene of which he was apprehended redhanded. To this he pleaded guilty.6

The next indictments (Nos. 7A, 7B, 7C, 7D, 7E and 10) charged separate burglaries which were encompassed by the challenged confession. Wayman moved to suppress his statement and after that motion was heard and denied, pleaded not guilty at No. 7E and went to trial before a jury. He was convicted. He then pleaded guilty to the remaining five indictments (Nos. 7A through 7D, inclusive, and 10). At no time has he moved the lower court to allow withdrawal of his guilty pleas.7

*91The legal issue which is now before us is easy to state: What must an appellant such as Wayman show in order to avoid guilty pleas when those pleas are alleged to be in some manner causally related to the presence in the hands of the prosecutor of illegally obtained evidence? We answered this question in Commonwealth v. Marsh, supra, in which we adopted the federal standards announced in the so-called “Brady trilogy” of the United States Supreme Court cases.8 We said in Marsh: “The United States Supreme Court [in McMann and Parker, supra note 8] held that a defendant must demonstrate all of the following to successfully collaterally attack a plea of guilty on such grounds: (1) an involuntary pretrial confession (or presumably any other constitutionally infirm incriminating evidence) ; (2) that the guilty plea was primarily motivated by such evidence; and, (3) that defendant was incompetently advised by counsel to plead guilty, in the circumstances, rather than stand trial. . . .

“We recognize that we could fix more exacting standards . . . for our courts to follow in determining the validity of conviction resulting from guilty pleas, and some of our previous decisions may have been so *92interpreted, but we intend to adhere to the rulings in McMann, supra, and Parker, supra.” 440 Pa. at 593-94. This statement of the law has been consistently followed in our subsequent decisions.9

I note that the first two of these requirements, as recited in Marsh, constitutes a restatement of the preMarsh law in Pennsylvania to which the Court today reverts: a guilty plea is avoided by showing a link of “but for” causation between the illegally obtained evidence and the plea.10 The third requirement of Marsh— *93that the plea shall have been entered on incompetent advice of counsel—was adopted from McMann v. Richardson, the trilogy case in which the role of counsel is most fully explicated. It should be noted, however, that the requirement appears in Brady and Parker as well, and that Marsh is in fact supported not only by McMann but by the principles of all three cases. This last requirement is completely overlooked by the majority.

I for one believe that a guilty plea, not withdrawn before sentencing, entered in accordance with the rules and decisions regarding guilty pleas,11 and competently *94advised by counsel, should be in practical effect final. I recognize, of course, that this Court has an independent power to depart from the federal constitutional law as announced by the Supreme Court of the United States and to require procedures more favorable to the defendant as a matter of state law. When as here that Court bas dealt with the subject extensively, I think this Court owes it to its constituency to explain why a different rule should obtain in Pennsylvania. That obligation is not discharged by the conclusory discussion of today’s opinion.

*95III.

Examining Wayman’s guilty pleas in the light of Marsh, we can dispose of this case without a remand. The record before us is adequate to resolve the only question which we need to reach: whether or not “defendant was incompetently advised by counsel to plead guilty, in the circumstances, rather than stand trial.” Commonwealth v. Marsh, supra, 440 Pa. at 593.

Wayman’s attorney moved to suppress the confession on the only arguable ground then open to him: failure to give Miranda warnings. He cannot be faulted for not raising the Futch issue; attorneys do not act incompetently merely because they fail to foresee a change in the law five years in the offing. Having presented a suppression motion on his client’s behalf which turned on factual issues (whether Miranda warnings had been given), and having seen those factual issues resolved adversely to his client on the strength of substantial evidence, Wayman’s attorney was acting reasonably in suggesting a guilty plea. Commonwealth v. Taylor, 449 Pa. 345, 296 A. 2d 823 (1972). I would affirm all of appellant Wayman’s judgments of sentence.