Defendants Mark Lewis Singer, Oakley Bechtel Cline, III, Arturo Izquierdo, Joseph Michael Sazenski, and John Patrick Reynolds appeal from their convictions on a number of drug-related offenses. The principal question presented is whether the District Court so far injected itself into the trial as to give the jury the impression that it favored the prosecution, thus depriving defendants of a fair trial. Although this is by no means a case of actual bias on the part of the trial judge, our review of the record constrains us to hold that his repeated remarks in the presence of the jury, culminating in a reference to his “helping the Government to try its case,” prevented the defendants from having their guilt or innocence determined in a proceeding free of a fatal appearance of unfairness. We therefore, in the exercise of our supervisory power over the administration of criminal justice in this Circuit, reverse the judgments of conviction and remand this case for a new trial.
I.
This case was originally submitted to a panel of this Court, and an opinion was filed affirming the convictions, one judge dissenting. United States v. Singer, 687 F.2d 1135 (8th Cir.1982). We adopt the statement of facts contained in part I of the panel opinion. We also adopt parts III and IV of the panel opinion. Specifically, we agree with the panel that the grounds urged by appellants in support of reversal (apart from the question of the District Court’s conduct of the trial) are without merit. The panel’s unanimous decision rejecting each of these grounds is adopted and reaffirmed.
II.
This case was tried before a jury from December 8,1980, to December 18,1980. It was a complex multi-defendant trial, with each of the six1 defendants who went to trial retaining his own lawyer. An Assistant United States Attorney tried the case on the government side alone. The District Court early became dissatisfied with the conduct of the government’s case. On December 10, the third day of the trial, the court summoned the United States Attorney to a conference in chambers. The conference began as follows (Tr. 311):
THE COURT: You may recognize an array of faces as being the cream of the crop of the Criminal Bar of the State of *433Minnesota, most of them specializing in Federal practice.
Yesterday I wrote a note which was delivered to Mr. Berg [the United States Attorney] which said I thought he ought to have a backup man for [the Assistant United States Attorney trying the case] in Court here. It’s Christmastime, it’s the beginning of winter, it’s the flu time, and I thought we don’t want this case delayed because we lost somebody.
Now I could go on to give you some other reasons why I thought you should have a backup man. But can’t you assign somebody up here this morning to start with us?
Mr. Berg declined. The District Court then ordered the United States to send another Assistant United States Attorney “to second-chair this man. That’s an order. And we’ll wait until he comes, before we go on with the case.... And if he is not here by noon, I will dismiss the case” (Tr. 312-13). The United States Attorney asked for a recess to consider the matter, following which the judge relented and agreed to allow the trial to proceed without additional counsel on the prosecution side. The court warned that “I am not going to try the Government’s case for it, like I’ve been doing up to this time ” (Tr. 317) (emphasis ours).
The trial judge nevertheless continued to help government counsel in the presence of the jury. As the trial continued, the court helped the government again and again. The judge admonished the prosecutor:
You’ve just about got that question so that it’s unintelligible because it’s about four questions in one.
What do you want him to say?, did he look at the stuff coming back from Minnesota? (Tr. 1057).
He instructed him on when, how, and on what grounds to object.
THE COURT: ... [W]hat are you doing there?
[GOVERNMENT COUNSEL]: Your Honor, I was just considering making an objection, objecting on the grounds of lack of relevance.
THE COURT: Well, that’s a good thought. You are still here, however, aren’t you?
[GOVERNMENT COUNSEL]: Yes, I am, Your Honor, I am objecting.
THE COURT: Have you thought anything about repetitiveness?
[GOVERNMENT COUNSEL]: Your Honor, I object also on the grounds of repetitiveness.
THE COURT: All right. Now when you come to a specific question, you make the objection and let me rule on it.
The question has been asked and answered now, but you might be just a little more aggressive here — or we’ll be here for a month (Tr. 630-31).
The judge was concerned that government counsel elicit testimony properly and avoid objections. “Just a minute. Lay a little more foundation than that. ‘Was there a time when another person came?’ That’s the way you do that, you see?” (Tr. 677). He directed government counsel when to end questioning (Tr. 789), and, apparently exasperated over the inability of government counsel to examine a witness properly, he took over the questioning himself.
REDIRECT EXAMINATION:
[BY GOVERNMENT COUNSEL]:
Q. You’ve described material you seized as marijuana?
MR. RESNICK: I will object to the reference to it as marijuana because it has not yet been identified as that.
THE COURT: Lay the foundation.
[GOVERNMENT COUNSEL]: Yes.
[GOVERNMENT COUNSEL]:
Q. Did you see some material—
THE COURT: Wait, wait.
Does he know marijuana from a bale of hay?
[GOVERNMENT COUNSEL]:
Q. Do you know what marijuana looks like?
A. Yes, I do.
*434MR. RESNICK: I object to that as lack of proper foundation.
THE COURT: How does he know?
[GOVERNMENT COUNSEL]:
Q. How do you know what marijuana looks like?
A. Because I’ve come in contact with marijuana on numerous occasions in the course of my duties with .the Police Department.
$ ¡js ¡}s * sfc sf:
Q. Could you describe what the substance looked like that you seized?
THE COURT: Now, let’s talk about what marijuana looks like.
[GOVERNMENT COUNSEL]:
Q. What does marijuana look like?
THE COURT: In a bale.
A. Marijuana in a bale — just like a hay bale, but it’s wrapped up, usually, in burlap, sometimes in plastic.
MR. RESNICK: I will object to the packaging. He asked what marijuana looks like, Your Honor. Not responsive to the question.
THE COURT: I think there is something to that. Let’s look at the material. You know, if you saw a truck riding down the street and it had little windows in it, would you say there were horses in there?
A. Yes, I would, Your Honor.
THE COURT: You would?
Wouldn’t it take a kind of a little smell to confirm that?
(Laughter.)
A. Yes, Your Honor.
THE COURT: What does marijuana look like, what does it smell like, what does it feel like?
If you know all of those things, we’ll let you go on.
If you don’t, we’ll send you back to Florida.
THE COURT: Ask him a question please.
I’ve given you a hint as to what you might ask him.
[GOVERNMENT COUNSEL]: Yes.
[BY GOVERNMENT COUNSEL]:
Q. Would you tell the members of the jury what marijuana looks like and smells like, just a physical description?
THE COURT: One question at a time.
[BY GOVERNMENT COUNSEL]:
Q. What does marijuana look like?
THE COURT: What color is it?
A. Sometimes it’s green, sometimes it’s gold, goldish-tan color, depending on where it comes from.
THE COURT: What is the texture of it? What do the little things look like?
A. It has the texture of a leaf. And the marijuana plant has five leaves on it.
[GOVERNMENT COUNSEL]: Okay, I’ll go on to the—
THE COURT: Does it have any seeds in it?
[BY GOVERNMENT COUNSEL]:
Q. Does it have seeds on it?
A. Yes, it does.
THE COURT: Do the leaves have any little pointees [sic] on them? (Tr. 648-53).
These examples are only illustrations. The trial court injected itself into the proceedings in a similar fashion on several other occasions. See, e.g., Tr. 677, 1014r-15, 1057.
Matters came to a head on Monday, December 15, 1980, the sixth day of trial. That morning, government counsel of his own accord corrected a statement he had made earlier to the effect that Izquierdo’s fingerprints had been found on a certain lease application. Counsel for Izquierdo moved for a mistrial.2 The District Court (properly) found that the prosecutor’s error had been unintentional. When Izquierdo’s *435lawyer then attempted to press his motion, the court interrupted him (Tr. 974):
THE COURT: Hey, there’s one lawyer up here who I wanted them to get some help for, and they won’t send him any.
MR. RESNICK: Well, that’s not my fault.
THE COURT: And he’s just about overwhelmed.
Now, Jurors, there is no fingerprint of Mr. Izquierdo on that thing.
Mr. Sehermer made a mistake.
So I think you can put that out of your mind, can’t you, Jurors?
(Jurors nod their heads affirmatively.)
THE COURT: The motion for mistrial is denied.
The jury is to disregard that.
It didn’t happen.
It was a mistake.
Later that day, during a conference in chambers, the defense again moved for a mistrial, this time on the ground that, because of the court’s remarks earlier that day, “they’re [the jury] going to feel sorry for this guy [the Assistant United States Attorney], and as a result it’s going to redound to our prejudice” (Tr. 1022-23). The court denied the motion, observing (Tr. 1025- 26):
I am not letting Sehermer make mistakes. He’s tried to make several of them, and I just must concede that I have straightened him out.
And I asked U.S. Attorney Tom Berg to send somebody up here to help him, and Berg wouldn’t do it.
But the statement I made to the jury about this man being overwhelmed was unfortunate — but I am going to straighten that out for you.
And I will straighten them out on the one mistake which I made, which was to say that Sehermer was overwhelmed; and — even though it’s true — I will straighten it out.
The jurors then returned to the courtroom, and the following took place (Tr. 1026- 27):
THE COURT: Ladies and Gentlemen of the jury, I should tell you something.
I made a mistake, and it really probably isn’t even factually true.
When Mr. Sehermer made that mistake where he said the wrong fingerprints were on the exhibit — he said the fingerprints were from a room that was rented over there, whereas in reality the fingerprints were in what he claims is a drug book — do you remember that?
(The jurors nod affirmatively.)
THE COURT: —that was a mistake he made.
I made a mistake, too, in trying to get this in perspective and set up so that you would understand it, and I said, “Well, Schermer’s busy and he’s overwhelmed.”
Well, he is not overwhelmed.
He represents the Government; and if the Government can’t send enough people up here to do their case right, then they deserve to lose if — by so doing — they don’t get the evidence in and make mistakes and mess up the case.
So don’t go feeling sorry for Sehermer. He’s tried dozens of cases for the Federal Department of Justice, criminal income-tax cases, he’s tried narcotics cases, he’s done all kinds of things, and he has wonderful credentials.
Sometimes I make him do it my way, but don’t go feeling sorry for him.
And I’m sorry I said that.
He is not overwhelmed.
He is a tiger.
Go ahead.
MR. SCHERMER: Thank you, Your Honor.
In context, the remark about counsel’s being “a tiger” could not have been taken seriously.
A few minutes later, the court again interrupted government counsel, this time to keep him from what would apparently have been a breach of an agreement about the proper scope of a witness’s examination. The judge instructed counsel as to how to proceed, addressed the witness directly himself, and then stated to the jury: “Now I *436hope you don’t object to my helping the Government to try its case, Ladies and Gentlemen, and Counsel ... (Tr. 1029).
We have carefully studied the entire transcript of the trial, amounting to over 1,800 pages, and the passages we have quoted are a fair sampling. To be sure, every intervention by the trial court in the proceedings was not on the side of the government, and some of the comments that the court made may have been helpful to the defense. It is nevertheless true that most of the court’s interventions were designed to clarify government testimony, to help government counsel, to indicate to government counsel when he should or should not make objections, to instruct government counsel on how to make his evidence more intelligible, to suggest to him when he should stop the examination of a witness, to indicate to him what he should write on a blackboard in order to illustrate a point to the jury, and the like. In addition, on numerous occasions the court took over the questioning of government witnesses in order to make sure that the somewhat complicated facts of this case were clearly explained. On the whole, it seems clear to us that the court believed the evidence of the defendants’ guilt was strong, but that the case was a complicated one, and that justice might not be done if government counsel were left to his own devices.
While it is a judge’s privilege and duty to take an active part in the trial where necessary to clarify evidence and assist the jury, a judge must studiously avoid one-sidedness. See Quercia v. United States, 289 U.S. 466, 470, 53 S.Ct. 698, 699, 77 L.Ed. 1321 (1933). In the case at hand the jury could well have inferred that the judge was siding with the government. While he undoubtedly thought that by aiding and correcting the government attorney, he was merely redressing the balance between several reputable defense lawyers and one “overwhelmed” government attorney, the obvious effects were 1) to place the defense at a disadvantage in the eyes of the jury by casting the prosecutor in the role of an underdog, United States v. Haley, 452 F.2d 391, 396 n. 2 (8th Cir.1971), cert. denied, 405 U.S. 978, 92 S.Ct. 1205, 31 L.Ed.2d 253 (1972); United States v. Guglielmini, 384 F.2d 602 (2d Cir.1967), and 2) to suggest to the jury that he favored the government’s position.3
A few improper comments are not necessarily enough to require reversal. United States v. Porter, 441 F.2d 1204 (8th Cir.), cert. denied, 404 U.S. 911, 92 S.Ct. 238, 30 L.Ed.2d 184 (1971). Each case must turn on its own circumstances. Here, the judge injected himself into the trial throughout the entire proceeding. Chief Justice Hughes observed in Quercia v. United States, supra, 289 U.S. at 470, 53 S.Ct. at 699, that a judge’s
privilege of comment in order to give appropriate assistance to the jury is too important to be left without safeguards against abuses. The influence of the trial judge on the jury “is necessarily and properly of great weight” and “his lightest word or intimation is received with deference, and may prove controlling.” .. , Starr v. United States, 153 U.S. 614, 626, 14 S.Ct. 919, 923, 38 L.Ed. 841.
We have recently had occasion to explain the legal principles applicable in this kind of situation. In United States v. Bland, 697 F.2d 262, 265-66 (8th Cir.1983), we said:
This Court has always been reluctant to disturb a judgment of conviction by reason of a few isolated, allegedly prejudicial comments of a trial judge. This is particularly true in a long trial. In each case a balancing process must be employed to determine whether the trial judge’s comments have pervaded the overall fairness of the proceedings. We think the balance is adversely tipped against the defendant in a criminal trial where the judge’s role loses its color of neutrality and tends to accentuate and emphasize the prosecution’s case. A trial *437judge s isolated questioning to clarify ambiguities is one thing; however, a trial judge cannot assume' the mantle of an advocate and take over the cross-examination for the government to merely emphasize the government’s proof or to question the credibility of the defendant and his witnesses. A judge’s slightest indication that he favors the government’s case can have an immeasurable effect upon a jury. A trial judge should seldom intervene in the questioning of a witness and then only to clarify isolated testimony. A trial court should never assume the burden of direct or cross-examination.
(Footnotes and citations omitted) (emphasis supplied).
No two cases are alike, and there are differences between Bland and the case before us. The trial in Bland was much shorter, and there the defendant himself took the witness stand. Here, defendants did not testify, and the trial took a total of ten days, including voir dire, argument, instructions, and jury deliberation. On the other hand, the evidence against the defendant in Bland, was, if anything, even stronger than the case made against the defendants before us on this appeal. In Bland, the charge was possession of an unregistered firearm by a felon, and a police officer actually saw Bland with a sawed-off shotgun in his hands. 697 F.2d at 263.
We recognize that these are matters of judgment and degree, about which reasonable judges may and do differ. We conclude, however, that what was said in Egan v. United States, 287 F. 958, 971 (D.C.Cir. 1923), is apt here: “While there is perhaps no single instance involving error so prejudicial as to warrant reversal, we are convinced that, considered as a whole, the rights of defendant[s] were so prejudiced thereby as to deprive [them] of that fair and impartial trial which the Constitution and the law of the land accords to every citizen accused of the commission of crime.” In short, our review of the entire record convinces us that the conduct of this trial fell below the Plimsoll line4 of fairness and the appearance of fairness.5
Accordingly, the judgments are reversed, and these causes are remanded to the District Court for further proceedings consistent with this opinion.
. The co-defendant Scott Cline was acquitted by the jury.
. This was not the first motion for mistrial. On December 9, 1980, the second day of testimony, a motion for mistrial was made on the ground that the court had explained a certain defense contention to the jury in such a way as to minimize or belittle it. Tr. 157. In all, 15 motions for mistrial were made during the course of the trial.
. The trial judge had told the jury panel during voir dire that he had served as United States Attorney (Tr. 7).
. See Fikes v. Alabama, 352 U.S. 191, 198, 199, 77 S.Ct. 281, 285, 285, 1 L.Ed.2d 246 (1957) (Frankfurter, J., joined by Brennan, J., concurring).
. The dissenting opinion, citing United States v. Hasting, ___ U.S. ___, 103 S.Ct. 1974, 76 L.Ed.2d 96 (U.S.1983), suggests that these convictions are being reversed “without proper weight to the relevant interests involved.” Post, p. 439. We disagree. In Hasting, a court of appeals had reversed a conviction without considering whether the error it found was harmless, and the Supreme Court did not approve. Here, we have considered the trial court’s conduct in the context of all the evidence presented, and we cannot say that there is no “ ‘reasonable possibility that the [practice] complained of might have contributed to the conviction.’ ” United States v. Hasting, supra, ___ U.S. at ___, 103 S.Ct. at 1979, quoting Fahy v. Connecticut, 375 U.S. 85, 86-87, 84 S.Ct. 229, 230, 11 L.Ed.2d 171 (1963).