*115We shall consider plaintiffs assignments of error concerning the trial court’s instructions first. The two basic issues are whether plaintiff was entitled to an instruction on G.S. 20-71.1 and whether a peremptory instruction was properly given in favor of defendant Charles Caldwell. We conclude that the trial court committed error in both regards and order a new trial on the agency issue.
 It cannot be questioned that G.S. 20-71.1 was applicable to this case. As explained by the Court in Duckworth v. Metcalf, the statute essentially provides that:
[p]roof of ownership of the automobile by one not the driver makes out a prima facie case of agency of the driver for the owner at the time of the driver’s negligent act of omission, but it does not compel a verdict against the owner upon the principle of respondeat superior.
268 N.C. 340, 343, 150 S.E. 2d 485, 488 (1966). It was stipulated that defendant Charles Caldwell was the registered owner of the vehicle at the time of the accident. Clearly, the judge had a duty to explain the rule of G.S. 20-71.1, even absent a special request by plaintiff, because it was the law arising from the evidence. G.S. 1A-1, Rule 51; Shuford, N.C. Civil Practice and Procedure § 51-3(1975). Moreover, this instruction was required even though plaintiff presented no positive evidence that Hooper was Caldwell’s agent. Whiteside v. McCarson, 250 N.C. 673, 110 S.E. 2d 295 (1959); Hartley v. Smith, 239 N.C. 170, 79 S.E. 2d 767 (1954). We note that a model instruction is available as a guide for explaining G.S. 20-71.1 to the jury. N.C.P.I. — Civ. 103.40 (1973).
 Nevertheless, the judge gave the following peremptory instruction for defendant:
Now, we have an issue here which is the first issue which says this: Was the Defendant Phillip McIntyre Hooper, at the time of the collision, acting as the agent of the Defendant Charles Kenneth Caldwell?
As to this issue, members of the jury, which is number one, if the jury finds that on the occasion of the collision on June 30, 1976, that the Defendant Hooper was driving the Defendant Charles Kenneth Caldwell’s car at Long Beach *116and that the Defendant Hooper was not on a mission or errand of any kind for the Defendant Charles Kenneth Caldwell, as all of the evidence tends to show, it would be your duty to answer issue number one “no.”
A peremptory instruction may be given in a proper case. Generally, “[t]his device may be used when there is a sufficient quantum of evidence, all tending to establish one side of an issue, and which, if credible, gives rise as a matter of law to but one permissible inference.” 2 McIntosh, N.C. Practice 2d, § 1516, at 42-43 (Supp. 1970). Specifically, it has been held repeatedly that defendant is entitled to a peremptory instruction when plaintiff relies solely on G.S. 20-71.1, and defendant offers un-contradicted evidence on the issue of agency tending to show that the driver was on a purely personal mission or errand at the time of the collision. Torres v. Smith, 269 N.C. 546, 153 S.E. 2d 129 (1967); Passmore v. Smith, 266 N.C. 717, 147 S.E. 2d 238 (1966); Nolan v. Boulware, 21 N.C. App. 347, 204 S.E. 2d 701, cert. den., 285 N.C. 590, 206 S.E. 2d 863 (1974). The case before us does not meet this test.
Plaintiff relied solely on G.S. 20-71.1 and did not offer independent proof of agency. Defense counsel did not present any evidence to rebut plaintiffs prima facie case of agency under the statute. There is no authority that a peremptory instruction may be given in favor of a defendant who offers no evidence whatsoever on the critical issue. Therefore, it was error to instruct the jury that all of the evidence tended to show that defendant Hooper was not on a mission for Charles Caldwell. The only evidence that even had this tendency was a pretrial stipulation which provided that “the Defendant Janet P. Caldwell had the vehicle in her custody and control and the right to exercise all incidents of ownership of the automobile as to its operation.”
Defendant contends that this stipulation had the effect of negating plaintiffs prima facie case under the statute and thus required plaintiff to come forward with independent proof of agency. We do not agree. It is significant that the stipulation did not say that Janet Caldwell had exclusive custody and control of the car. Moreover, it did not provide that she had all incidents of ownership with respect to the car. It merely stated that she had the right to exercise all incidents of ownership. The stipula*117tion did not, therefore, exclude the possibility that Hooper was acting as Charles Caldwell’s agent at the time of the collision. We must conclude that this stipulation was not positive, uncon-tradicted evidence of the lack of agency sufficient to require a peremptory instruction. Giving a peremptory instruction in this case defeated the plain and obvious purpose of G.S. 20-71.1, which is to enable plaintiff to submit a prima facie case of agency to the jury which it can decide to accept or reject. Chappell v. Dean, 258 N.C. 412, 128 S.E. 2d 830 (1963); Travis v. Duckworth, 237 N.C. 471, 75 S.E. 2d 309 (1953). A peremptory instruction is warranted only when compelling evidence permitting one reasonable conclusion is presented; otherwise, this procedural device could be used to reduce G.S. 20-71.1 to a meaningless exercise.
Though it is not necessary to our disposition here, we agree with two other contentions made by plaintiff. First, the judge expressed an improper opinion in his opening instructions on what the evidence tended to show on the agency issue when he said that “at the proper time in my charge I will instruct you that on the basis of the evidence that you will answer that issue ‘no.’ ” Such a comment on the evidence is prohibited by G.S. 1A-1, Rule 51(a). The remark was so absolute that a juror may have believed that the judge had already given the correct conclusion. See Shuford, N.C. Civil Practice and Procedure § 51-4 (1975). Second, the form of the peremptory instruction was also incorrect. When G.S. 20-71.1 applies to a case, the instruction must relate directly to particular facts shown by defendant’s positive evidence. Belmany v. Overton, 270 N.C. 400, 154 S.E. 2d 538 (1967); Whiteside v. McCarson, 250 N.C. 673, 110 S.E. 2d 295 (1959).
Plaintiff’s final assignment of error is that the court erred in denying his motion for a new trial on the ground of inadequate damages for decedent’s pain and suffering. We decline to grant a new trial on this issue. The judge’s decision on the matter was within his discretion, and we can find no abuse of discretion here. Robinson v. Taylor, 257 N.C. 668, 127 S.E. 2d 243 (1962); Gwaltney v. Keaton, 29 N.C. App. 91, 223 S.E. 2d 506 (1976). Thus, in addition to the trial court’s order of a new trial on damages for decedent’s present monetary value, we order a new trial on the agency issue.
Judges Martin (Robert M.) and Webb concur.