R.M. MAHER, P.J.

Defendant was placed on 3 years probation after his conviction for unlawfully driving away an automobile. While on probation, he was convicted of attempted uttering and publishing and sentenced to 2 years probation, the first 6 months to be served in the Detroit House of Corrections. Because of the second conviction, defendant was found guilty of violating probation for the first conviction and sentenced to a term of from 2 to 5 years in prison to run concurrently with the sentence imposed for attempted uttering and publishing. Defendant appeals, raising two issues of merit.

I

Defendant claims the trial court committed reversible error when it failed to give him a written copy of the charges constituting violation of his probation. MCLA 771.4; MSA 28.1134 provides, "[t]hat the probationer shall be entitled to a written copy of the charges against him which constitute the claim that he violated his probation". The trial court in the present case did fail in this regard, but plaintiff maintains, on the authority of In re Cobos, 326 Mich. 537; 40 N.W.2d 717 (1950), that the error was not prejudicial.

Defendant, in the case of In re Cobos, supra at 538, claimed that because he was not afforded his statutory right to "a written copy of the charges against him which constituted the claim that he violated his probation", the trial court "was without jurisdiction to revoke the order of probation and to impose the sentence under which he [was] imprisoned". The Michigan Supreme Court "concluded [from the record] that counsel [for defendant Cobos] were aware of their client's right to be served with a written copy of the charges". In re McLeod, 348 Mich. 434, 439; 83 N.W.2d 340 (1957). The Court found, therefore, that failure by counsel to request written notice of the claimed violation, when coupled with their announcement that they were ready to proceed and the fact that defendant was convicted a few days earlier of the offense which was the substance of defendant's probation violation, constituted a deliberate waiver of defendant's statutory right. See In re McLeod, supra. The Court could see no prejudice to defendant and dismissed his writ of habeas corpus.

Notwithstanding, the United States Supreme Court decided in Morrissey v Brewer, 408 U.S. 471; 92 S Ct 2593; 33 L Ed 2d 484 (1972), as applied to probation revocation proceedings in Gagnon v Scarpelli, 411 U.S. 778, 93 S Ct 1756; 36 L Ed 2d 656 (1973), the minimum due process requirements for a probation revocation hearing:

"They include (a) written notice of the claimed violations of [probation]; (b) disclosure to the [probationer] of evidence against him; (c) opportunity to be heard in person and to present witnesses and documentary evidence; (d) the right to confront and cross-examine adverse witnesses (unless the hearing officer specifically finds good cause for not allowing confrontation); (e) a `neutral and detached' hearing body * * *; and (f) a written statement by the factfinders as to the evidence relied on and reasons for revoking [probation]." Morrissey v Brewer, supra, 408 US at 489. (Emphasis supplied.)

Regardless, therefore, of defendant's rights under MCLA 771.4; MSA 28.1134, due process requires that he receive written notice of the claimed violations of probation and we can find no express waiver of that right on this record.

II

The next question is whether defendant had a right to have the probation revocation hearing held within a reasonable time after the violation occurred and whether the failure to conduct such a hearing until 6 months had elapsed constituted an abridgment of that right.

On the attempted uttering and publishing conviction, defendant was sentenced to 2 years probation with the first 6 months to be served in the Detroit House of Corrections. The probation authorities did not serve defendant with the warrant for probation violation until the last day of the 6-month term. This Court has recently held that a warrant for an alleged probation violation must be executed with due diligence and that failure on the part of the authorities to proceed with due diligence results in a waiver of the violation. People v Diamond, 59 Mich. App. 581; 229 N.W.2d 857 (1975), lv den, 394 Mich. 824 (1975). It is difficult for us to imagine that the probation authorities were ignorant of defendant's incarceration and that they were unable to execute the warrant until the day of his release. However, that is a question for the trial court.

We recognize that the decision in People v Diamond, supra, was released some 10 months after defendant was found guilty of probation violation. We believe, however, that the rule set out in Diamond, supra, should apply to the case at bar. The three criteria for determining retroactivity are: (1) the purpose of the new standard; (2) the justified reliance on the old standard; and (3) effect on the administration of justice if the new test is applied retroactively. People v Fields, 391 Mich. 206; 216 N.W.2d 51 (1974).

The obvious purpose of the new rule is to assure probationers speedy disposition of probation violation charges. Any claim of justifiable reliance by probation authorities upon a practice of waiting a period of time before executing a warrant would not be convincing, particularly not since the release of this Court's decision in People v Hallaway, 39 Mich. App. 74; 197 N.W.2d 335 (1972). There we stated:

"While we affirm the imposition of sentence following the probation revocation hearing, we do not wish to be understood as condoning proceedings so long delayed. Had the defendant not been given the benefit of time served on the first sentence towards the second, this Court would have considered whether In re Evans, 18 Mich. App. 426 [; 171 N.W.2d 499] (1969) (where this Court held that an allegedly delinquent parolee has a right to have the parole board exercise reasonable diligence in seeking to have a revocation hearing), could or should be applied to a probation revocation hearing." 39 Mich App at 76-77.

Hallaway placed the authorities on notice that undue delay in acting on charges of probation violation would not be tolerated and we find our decision in Diamond to apply to the instant case, as well as to any case following the release of the Hallaway decision. Any negative effect our holding might have upon the administration of justice will be far outweighed by the positive.

III

Failure to provide defendant with written notice of the charges against him requires that the order revoking probation be set aside, the sentence vacated and defendant remanded to the custody of the trial court. The trial court will then conduct a hearing to determine from all the facts and circumstances of this case whether the 6 month time lapse between issuance of the warrant for violation of probation and its execution constituted a waiver of the violation. If the court finds that the authorities were diligent in their actions, the court will then be without prejudice to conduct a proper probation revocation hearing. We retain no further jurisdiction.