Defendant appeals from a judgment convicting him of the crime of feloniously possessing narcotics (Penal Law, § 1751). We are satisfied that he is guilty beyond question. However, it is urged that there must be a reversal and a new trial because a witness had previously been promised leniency by the District Attorney in return for his co-operation in prosecuting the defendant, and that fact was not disclosed by either the District Attorney or the witness.
*243Before defendant’s arrest, this witness, Mantzinos, was apprehended, implicated the defendant, and pleaded guilty to a violation of section 1751. At the time of his plea, the assistant district attorney stated in open court his “ understanding that [upon] continued, truthful co-operation on the part of the defendant I will permit the withdrawal of that plea and permit the defendant to plead to an attempt under that first count, which brings with it no mandatory minimum ”. After defendant’s conviction, Mantzinos was permitted to withdraw his original plea and enter a plea of guilt to the lesser charge, the prosecutor stating: “ I am certain that his testimony in fact was the ultimate factor in convicting [appellant] * * * who was found guilty of the charge.” Mantzinos was sentenced for a term of one to two years, with execution thereof suspended.
At his trial, defendant was apparently unaware of Mantzinos ’ promise of leniency for ‘ ‘ truthful co-operation. ’ ’ This circumstance is said by appellant to lend impact to the following direct examination of Mantzinos by the same prosecutor previously quoted:
“ Q. Were you convicted of or did you plead guilty to the crime of feloniously posessing a narcotic drug with intent to sell? A. I pleaded guilty.
“ Q. And was that in this court of General Sessions? A. Yes, it was — I can’t remember well; I think it was here.
“ Q. To what did that plea apply? What did that plea involve, Mr. Mantzinos? A. Possession of narcotics that I received to sell. * * *
“ Q. Do you recall the date on which you pleaded guilty to the crime of possession of this Hashish? A. I pleaded guilty a week before that. * * *
“ Q. And the crime you pleaded guilty to was the possession of these 16 pieces of hashish, is that right? A. That’s right.” Although the direct testimony correctly stated the fact of Mantzinos’ plea, neither the District Attorney nor witness, by query or reply or otherwise, told of the ‘ ‘ understanding ’ ’ conditioned upon “ truthful co-operation ”.
On cross-examination, however, the picture was brought into somewhat better focus:
“Q. Do you expect any consideration in the way of fixing your punishment depending on the testimony and kind of testimony that you are giving here today? A. No.
“ The Court: You really do, of course, don’t you?
“ The Witness: Pardon me?
“ The Court: I mean you look forward with some degree of lively anticipation?
“ The Witness: Well =—
*244“ Q. Is the answer ‘ Yes ’, that yon do?
“ A. Well, I don’t do it particularly for that cause.
“ The Court: Do you look forward to it?
“ The Witness: No, I didn’t. I didn’t do it for that purpose.
“ Q. Do you hope now to have any consideration in view of the testimony — A. I have already pleaded guilty to the indictment. What else can I do?
‘ ‘ By the Court:
“ Q. The question is very simple. The question is do you look forward with some degree of optimism to the sentence to be imposed on you? A. Well, I don’t know how to answer that. I never looked forward, you know — well, I pleaded guilty, that is all there is. Whatever the sentence is, let it come.
“ By Mr. McNamara:
“ Q. You don’t care what the sentence is? A. I don’t care what the sentence is.
“ Q. You expect to be deported anyway, don’t you? A. Well, I suppose they will deport me. I don’t belong here to this country.” (Italics supplied.)
It is clear from the foregoing that the jurors were never told of the fact that Mantzinos, when he pleaded guilty to the crime of possessing narcotics, had been promised by the District Attorney that if he co-operated he would later be permitted to plead to a lesser crime with a lesser sentence. We are thus required to determine on this appeal whether these circumstances are sufficient to require a reversal of the judgment of conviction.
Ordinarily in a case that is free from doubt upon the merits, the appellate courts will disregard errors of the trial court, even in a criminal case, where it is reasonably certain that such errors could not have affected the result (People v. Fielding, 158 N. Y. 542, 550). Defendant’s guilt was established beyond a doubt. Apart from the other testimony in the case he had made a full confession, the truth and accuracy of which could not be challenged. Nevertheless, no matter how strong the evidence against a defendant may be, if it is shown that he did not have a fair trial a judgment of conviction will not be permitted to stand (People v. Carborano, 301 N. Y. 39; People v. Tassiello, 300 N. Y. 425; People v. Mleczko, 298 N. Y. 153; People v. Manganaro, 218 N. Y. 9; People v. Minkowitz, 220 N. Y. 399; People v. Wolf, 183 N. Y. 464).
Essentially, the only question we must decide here is whether the defendant in this case has had a fair trial. The only argument to support the claim that the trial was not a fair one is based, as we have indicated, on the failure of the District *245Attorney to disclose the agreement made with Mantzinos for leniency. The withholding of that information did not bear directly on any ultimate issue of fact to be decided by the jury. The only prejudice that could be claimed by the defendant would be that the jurors were prevented from properly assessing the credibility of Mantzinos. We do not underestimate the great importance of the question of Mantzinos’ credibility. We think, however, that it must have been clear to the jury from the nature of Mantzinos’ own testimony (quoted elsewhere herein), that he was expecting consideration. Also that fact was made quite plain to the jury by the Trial Judge in his charge, when in commenting on the testimony of Mantzinos he said: “ Only you can determine his credibility. Only you can decide what weight must be given to his testimony, but it is only fair to observe, I think, that Mantzinos was not only an accomplice but he was also a convicted criminal and I have no doubt whatever that he looked forward with the most lively anticipation to some reward for his testimony.”
A fair reading of Mantzinos’ testimony considered in the light of the court’s charge would indicate, we think, that the jurors had a good picture of the situation insofar as the question of expectant leniency was concerned. Had the District Attorney — as he should have done — made it known that there had been a promise of leniency to Mantzinos, the only effect would have been to emphasize the fact that he had an interest in testifying, for even without that disclosure it seems obvious from this record that the jurors knew that Mantzinos had such an interest.
Unquestionably, it was the District Attorney’s duty to disclose the agreement. But the question we are concerned with here is not whether the District Attorney, in failing to make the disclosure, was unfair, but whether the trial itself was unfair. In determining what constitutes a fair trial there is no fixed norm, the answer depending entirely upon the particular facts of each case. “ The decision in each case as to whether the trial was fair or unfair, whether the error was harmless or prejudicial, must of necessity depend upon the nature of the proof adduced and upon the type of error committed.” (People v. Carborano, 301 N. Y. 39, 43, supra.)
We fail to find on the particular facts of the present case that there is any reasonable basis for finding that the defendant did not have a fair trial.
We are mindful of the numerous cases in which convictions have been set aside because of improper conduct on the part of the prosecutor. Factually however, the present case is clearly distinguishable. The information withheld did not go directly *246to any ultimate question of fact to be determined by the jury. The most a disclosure of that information would have accomplished, as we have pointed out before, would have been to emphasize something that must have already been known to the jury, namely that the testimony of the witness was coupled with an interest.
We reach the conclusion therefore that the defendant was not prejudiced and that he had a fair trial, particularly in view of the court’s caveat to the jury with respect to their consideration of Mantzinos ’ testimony.
The judgment of conviction should be affirmed.