Opinion
WRIGHT, C. J.By petition for writ of habeas corpus petitioner challenges the part of a judgment sentencing him to a term of imprisonment that purports to limit the effect of sentencing under Penal Code section 1202b1 to a term imposed for the offense of robbeiy, while leaving unaffected an additional, consecutive term imposed upon a finding that he used a firearm within the meaning of section 12022.5.2
Pursuant to a plea bargain whereby a charged violation of section 217, an allegation that he caused great bodily injury to the robbery victim, *211and an allegation that he had suffered prior felony convictions were dismissed, petitioner pleaded guilty to first degree robbeiy (§§ 211, 213), and admitted the truth of allegations that he had been armed (§ 12022) with, and had used (§ 12022.5) a firearm in the commission thereof.3 The sentence to be imposed was not a condition of the bargain.
On September 27, 1972, the court sentenced petitioner to a term of imprisonment for the robbeiy, invoking section 1202b, and to a consecutive term of five years to life under section 12022.5 because he had used a firearm. Counsel had argued on behalf of petitioner that because petitioner’s offenses were the result of a serious narcotic problem the court should consider committing him to the California Rehabilitation Center even though the probation officer had expressed doubt that petitioner would be accepted for treatment. The court determined, however, that petitioner was not a suitable candidate for such treatment. Counsel also suggested other alternative dispositions among which was the sentence to imprisonment for the robbeiy under the terms of section 1202b, with an additional five-year-to-life term as provided by section 12022.5. The court expressed great concern over the serious injuries petitioner had inflicted on the victim and noted what the court perceived to be a propensity for violence in petitioner’s background. Notwithstanding that concern and an inability to find “any ray of light in this defendant’s background to afford any reasonable expectation that he’s going to be anything but in trouble,” and only after counsel assured the court that his understanding of section 1202b was that the section permitted the limitation of its effect to the robbery term alone, the judge accepted counsel’s suggestion.4 If authorized, this *212judgment would result in a cumulative minimum term of five and one-half years.
The court would have been more than justified in refusing to invoke section 1202b at all, but it nevertheless invoked that section because it had “some faith and confidence” in the Adult Authority which body, it hoped, “upon viewing this defendant’s background and history will be veiy careful about when, if ever, they release him into society.”
Petitioner now contends that this sentence is unauthorized by the terms of section 1202b. We agree. Habeas corpus is an appropriate means by which- to challenge an unauthorized sentence. (Neal v. State of California (1960) 55 Cal.2d 11, 16 [9 Cal.Rptr. 607, 357 P.2d 839].)
At the outset we note that notwithstanding what may appear to have been invited error, arising from his counsel’s misinterpretation of section 1202b, petitioner is not estopped to raise this issue. A court is without authority to impose a sentence not prescribed by statute. (§ 12; In re McInturff (1951) 37 Cal.2d 876, 879 [236 P.2d 574].) To the extent that a judgment imposing a term of imprisonment contains unauthorized surplusage, it is void. (In re Seeley (1946) 29 Cal.2d 294, 302-303 [176 P.2d 24].)
We turn first to an examination of the language of section 1202b. Provisions of the Penal Code must be construed “ ' “according to the fair import of their terms, with a view to effect its objects and to promote justice.” ’ [Citation.] Consistent with that general principle, appellate courts first examine the language of the code section to determine whether the words used unequivocally express the Legislature’s intent. If no ambiguity, uncertainty, or doubt about the meaning of the statute appear, the provision is to be applied according to its terms without further judicial construction.” (Morse v. Municipal Court (1974) 13 Cal.3d 149, 156 [118 Cal.Rptr. 14, 529 P.2d 46].) If ambiguity is found, the statute is to be interpreted “in the light of the objective sought to be achieved by it, as well as the evil sought to be averted.” (People v. Carroll (1970) 1 Cal.3d 581, 584 [83 Cal.Rptr. 176, 463 P.2d 400].)
*213Applying these rules we conclude that the language of section 1202b itself should be determinative.5 Section 1202b expressly provides that if the sentencing judge exercises his discretion to invoke its provisions in sentencing a youthful offender, he may “specify that the minimum term of imprisonment for the offense or the offenses cumulatively shall be six months.” There would seem to be no ambiguity in language which gives the judge the power to “specify that the minimum term of imprisonment . . . shall be six months.” The authority of the judge begins and ends with the direction that the minimum term is to be six months.
Respondent, however, argues that because the statute provides that the sentencing court “may” apply its provisions to any offense or offenses, it follows that it may fix the minimum term of any offense at six months and need not apply the six-month term to the whole judgment. The dissent, going beyond even that interpretation, suggests that the statute is susceptible to an interpretation that would permit the court to fix the minimum term or terms for any of the offenses at any period between six months and the minimum statutory term otherwise applicable. Both suggestions appear to overlook the plain language of the statute which authorizes the court to fix a single minimum term for all offenses cumulatively at six months. Even were we persuaded that the statute was ambiguous, however, such legislative history and “administrative” construction as does exist, both of which are entitled to great weight (People v. Superior Court (Carl W.) (1975) 15 Cal.3d 271, 277 [124 Cal.Rptr. 47, 539 P.2d 807]; City of Los Angeles v. Public Utilities Com. (1975) 15 Cal.3d 680, 696 [125 Cal.Rptr. 779, 542 P.2d 1371]), support our interpretation of the language, as do those cases in which we have heretofore had occasion to consider the application of section 1202b to sections 12022 and 12022.5.
Section 1202b was enacted in 1959. (Stats. 1959, ch. 916, § 1, p. 2948.) In the intervening 17 years sentencing judges have uniformly applied it by specifying that the defendant would serve a minimum term of 6 months. This is the first instance in which an appellate court has been called upon to review any othér attempted application. The principal criminal law practice manual published by the Continuing Education of the Bar has so interpreted section 1202b in chapters authored by now retired appellate Justice John F. Aiso6 who was a superior court judge *214when the section was enacted and by Everette M. Porter,7 who was a member of the Adult Authority at that time.
This interpretation is also consistent with the philosophy of the indeterminate sentence law and the only statement of the legislative purpose in enacting section 1202b that has come to our attention.
Under the indeterminate sentence law responsibility for fixing the length of time within the statutory maximum and minimum a convicted felon is to serve in prison and/or on parole is vested in the Adult Authority. (§§ 1168, 5077; In re Rodriguez (1975) 14 Cal.3d 639, 645 [122 Cal.Rptr. 552, 537 P.2d 384].) Until 1944, a sentencing judge was permitted to commit to the Youth Authority a defendant who had been under 23 years of age when apprehended (Stats. 1941, ch. 937, § 1, p. 2526), in order to “substitute] for retributive punishment[,] methods of training and treatment directed toward the correction and rehabilitation of young persons found guilty of public offenses.” (Welf. & Inst. Code, § 1700.) A youthful offender committed to the Youth Authority after conviction of a felony had to bé discharged when he reached his 25th birthday (Welf. & Inst. Code, § 1771) and might be discharged and/or paroled at any time the Youth Authority determined that he could be released without danger to the public. (Welf. & Inst. Code, §§ 1765, 1766.)
In 1944, however, the Youth Authority Act (Welf. & Inst. Code, § 1700 et seq.) was amended to lower the age of persons who might be committed to the Youth Authority to those who were under 21 years of age at the time of apprehension. (Stats. 1944, Third Ex. Sess., ch. 2, p. 22.) The result of the amendment was that persons formerly entitled to consideration for rehabilitative treatment as youthful offenders through commitment to the Youth Authority had to be committed to the Department of Corrections and became subject to the same restrictions relating to parole and discharge as applied to other adult felons, even though in many cases codefendants under 21 years of age whose culpability and relative level of maturity was the same, had been *215committed to the Youth Authority. This disparity continued until the enactment of section 1202b in 1959. (Stats. 1959, ch. 916, .§ 1, p. 2948.)
Although true “legislative history” is nonexistent, there is persuasive evidence that the purpose of section 1202b was to allow the sentencing judge to permit a young person, who prior to 1944 might have been committed to the Youth Authority, to be treated on a parity with persons still eligible for Youth Authority commitment with regard to parole eligibility and discharge. The 1944 amendments to the Youth Authority Act were part of the Prison Reorganization Act which reorganized the entire penal and correctional system of the state and established the Department of Corrections and Adult Authority. (Stats. 1944, Third Ex. Sess. ch. 2, p. 12.) The Youth Authority became a component part of the Department of Corrections (id., ch. 4, p. 17), and Richard A. McGee was appointed as the first Director of Corrections, the chief administrative officer of the department, by then Governor Warren. Mr. McGee continued in that capacity until 1961 when he became Administrator of the California Youth and Adult Corrections Agency, which position he held in 1965, when he participated in the First Sentencing Institute for Superior Court Judges sponsored by the Judicial Council of California. He was, therefore, knowledgeable about both Youth Authority and Adult Authority practices. During a panel discussion of the Adult Authority’s handling of persons sentenced under section 1202b, Mr. McGee noted the problem that had existed prior to its enactment in attempting to give similar treatment to youthful codefendants, one of whom had been committed to the Youth Authority. He explained: “I thought maybe a Tittle comment on the history of Penal Code Section 1202b might be of interest. You get a good many cases committed to the Youth Authority who are under 21 years of age and very often, more often than you think perhaps, there are co-defendants who are just past 21. The Youth Authority case might be out on the street in 18 months while the one who is committed as an adult and who is just past 21 won’t be eligible for parole until 20 months and would serve a minimum term of 5 years.” (First Sentencing Institute for Superior Court Judges, 45 Cal.Rptr. Appen., at pp. 110-111.) It is manifest that if the purpose of the Legislature in enacting section 1202b was to permit youthful offenders ineligible for commitment to the Youth Authority to be considered for parole and discharge on the same basis as their slightly younger codefendants, that purpose would not be served by the interpretations sought by respondent and the dissent.
Nor is this insight into the purpose of section 1202b newly gained. Even before Mr. McGee’s explanation of the. section’s purpose to the *216judges attending the sentencing institute, in the first reported appellate decision construing the section, the Court of Appeal had recognized it. The Department of Corrections had interpreted the mandatory minimum terms prior to parole eligibility established by the Health and Safety Code for certain narcotics offenses as being specific provisions which took precedence over section 1202b. The Court of Appeal, in In re Ward (1964) 227 Cal.App.2d 369 [38 Cal.Rptr. 650], held, however, that section 1202b was a special act and was controlling. In so doing, the court noted that this construction was consistent with the purpose of the Legislature that “the indeterminate sentence law and the Youth Authority Act should be construed and applied to work together as complementary parts of a more enlightened penal system. (People v. Ralph, 24 Cal.2d 575, 580.)” (227 Cal.App.2d at p. 375; see also People v. McCullin (1971) 19 Cal.App.3d 795, 800 [97 Cal.Rptr. 107].)
In both of the cases in which this court has since had occasion to' consider the applicability of section 1202b, we have recognized that once the sentencing judge has determined that the defendant is deserving of consideration as a youthful offender and has invoked section 1202b the minimum term of imprisonment may only be six months. In People v. Hicks (1971) 4 Cal.3d 757 [94 Cal.Rptr. 393, 484 P.2d 65], we held that when a defendant who had been convicted of robbery, as was petitioner here, and who had been found to have been “armed” with a firearm during the commission of that offense within the meaning of section 120228 was sentenced under section 1202b, the provisions of that section took precedence over the additional penalty provisions of section 12022. We stated that “by invoking section 1202b the court impliedly declared sections 3024 and 12022 inapplicable to this defendant.” (4 Cal.3d at p. 765; italics added.) Inasmuch as the language of section 12022.5 is in all relevant aspects identical to that of section 12022, there is no basis upon which to distinguish the effect of applying section 1202b to a defendant found to have used a weapon under section 12022.5 from the effect of applying section 1202b to a person found to have been armed with a deadly weapon under section 12022. Certainly there is no indication that the Legislature intended a different result.
*217Indeed, the effect of invoking section 1202b in the case of a youthful offender found to have used a firearm was before this court in People v. Chambers (1972) 7 Cal.3d 666 [102 Cal.Rptr. 776, 498 P.2d 1024].
Although in Chambers respondent did not suggest that any minimum term other than the six months expressly provided by section 1202b could be imposed by a court invoking that section in sentencing a youthful offender, and thus that question was not directly presented, Chambers is dispositive. In Chambers, as in Hicks, the court was called upon to determine the effect of invoking section 1202b. We held that when a trial court finds a defendant to be qualified for treatment as a youthful offender, and sentences him under section 1202b, “the youthful offender’s sentence shall be a minimum of six months to the maximum set by law.” (7 Cal.3d at p. 675.)
A trial judge has an obligation when sentencing a defendant meeting the criteria of section 1202b to determine whether there are factors which make the defendant deserving of treatment as a youthful offender. We emphasize that such treatment does not entitle the defendant to an earlier release on parole or discharge from custody than that otherwise applicable. Invoking section 1202b does no more than permit the Adult Authority to consider such release if, after observation and study of the defendant, the authority determines that his conduct and effort toward reformation confirm the sentencing court’s tentative determination that he in fact deserves treatment comparable to that available to younger defendants committed to the Youth Authority. In making that'initial judgment, the sentencing court should consider the defendant’s background, the circumstances of his offense, his relationship to any other participants who may have been committed to the Youth Authority, and any indicia of potential for reformation prior to the time he would be eligible for parole and/or discharge if section 1202b were not invoked. If the sentencing judge does conclude that the defendant is deserving of treatment as a youthful offender, and invokes section 1202b, that determination is for all purposes and applies to all terms imposed in that proceeding.
Notwithstanding his own reservations, and circumstances which would have fully justified denying 1202b consideration, the judge here elected to invoke that section. The purported limitation of section 1202b to the robbery term being in excess of the court’s power is of no effect and the Adult Authority is therefore directed to consider petitioner for term fixing and parole without regard thereto.
*218Inasmuch as petitioner is not now entitled to his release from custody, the order to show cause is discharged, and the petition for writ of habeas corpus denied.
Tobriner, J., Mosk, J., and Sullivan, J., concurred.
Unless otherwise specified all references herein are to the Penal Code.
Section 1202b provides: “In any criminal proceeding in which defendant is convicted of a felony or felonies and is committed to the custody of the Director of Corrections, if defendant was, at the time of commission of the offense or offenses, or of the apprehension from which the criminal proceeding resulted, under the age of 23 years, the court may, notwithstanding any other provision of law fixing or affecting the penalty for the offense or offenses, specify that the minimum term of imprisonment for the offense or the offenses cumulatively shall be six months. This section does not apply to any offense punishable by death.”
Section 12022.5 provides in pertinent part: “Any person who uses a firearm in the commission ... of a robbery, . . . shall, in addition to the punishment prescribed for the crime of which he has been convicted, be punished by imprisonment in the state prison for a period of not less than five years. Such additional period of imprisonment shall commence upon expiration or other termination of the sentence imposed for the crime of which he is convicted and shall not run concurrently with such sentence.”
If, as appears to be the case, the victim of assault was the robbery victim and the two offenses were committed with a single intent and objective as part of a single course of criminal conduct, sentence on the assault charge could not have been executed in any case. (§ 654; People v. Beamon (1973) 8 Cal.3d 625, 636-639 [105 Cal.Rptr. 681, 504 P.2d 905].) Petitioner did, however, receive a substantial benefit in the elimination of the allegation that he had intentionally caused great bodily injury to the robbery victim, which if admitted or proved would have increased the minimum term for the robbery from 5 years to 15 years. (§ 213.)
The court specified: “The defendant will be sentenced to the State Prison for the term prescribed by law for first degree robbery, which is five years to life. [¶] However, in connection with that sentence only, the Court will impose the conditions of 1202b of the Penal Code, making the minimum sentence six months. However, the Court additionally imposes the five years provided for in 12022.5 and directs that the commitment specifically indicate that the Court’s direction of invoking 1202b is not to apply to the conditions of section 12022.5 of the Penal Code.”
The court added: “I want the Adult Authority to know that this defendant has only one thing in his favor and that is his age. At this point in his life, he has indicated *212absolutely no concern for the welfare of others and that he should be considered for early parole only if his conduct in custody manifests a true orientation to the point where he has some regard for the physical well being of other people.”
For the full text of section 1202b, see footnote 1, ante.
Judge Aiso wrote in a chapter on sentencing that “if the defendant is under 23, the judge can include in his [1203.01] statement his recommendation under Pen C § 1202b *214that the defendant be given a minimum six-month term.” (2 Cal. Criminal Law Practice (Cont.Ed.Bar 1969) p. 203.)
In a chapter on state imprisonment and parole administration, Mr. Porter, a lawyer and court commissioner, wrote with regard to the powers of a sentencing judge under the Indeterminate Sentence Law (§ 1168): “In a few instances, the judge has limited power to affect duration:... if the defendant was under 23 when the crime was committed, the judge can specify a minimum (but not a maximum) sentence of six months (Pen C § 1202b;...)....” (Id., at p. 510.)
Section 12022 provides: “Any person who commits or attempts to commit any felony • within this state while armed with any of the deadly weapons, as defined by subdivision (f) of Section 3024, upon conviction of such felony or of an attempt to commit such felony, shall in addition to the punishment prescribed for the crime of which he has been convicted, be punishable by imprisonment in a state prison for not less than five nor more than 10 years. Such additional period of imprisonment shall commence upon the expiration or other termination of the sentence imposed for the crime of which he is convicted and shall not run concurrently with such sentence.”