—Order, Supreme Court, New York County (Marilyn Shafer, J.), entered December 28, 1999, which denied plaintiffs’ motion to set aside the jury verdict as against the weight of the evidence and to grant a new trial, reversed, on the facts and in the exercise of discretion, without costs, and the matter remanded for a new trial.
Plaintiff’s car, while stopped at an intersection, was hit in *391the rear by defendant’s car. Defendant denied having been involved in the accident, so that the fact of her involvement was the main focus of pre-trial proceedings and of the trial. The jury, presented with evidence supporting plaintiff’s negligence claim, found that defendant’s vehicle had, in fact, struck plaintiff’s car and adjudged defendant liable in negligence. However, the jury found that defendant’s negligence was not a substantial factor in causing plaintiff’s injuries, and this part of the verdict is presently being challenged.
While as a matter of course, we ordinarily refrain from disturbing such jury findings, fundamental error in this case deprived plaintiff of a fair trial on that issue. The IAS Court found the record to reflect that the parties initially agreed to conduct a bifurcated trial, which plaintiff believed to mean that evidence of injuries, including medical evidence, would not be presented in the liability portion of the trial. While this perception may have overlooked the need to present evidence of injuries pursuant to plaintiff’s obligation to prove proximate causation, nevertheless, the IAS Court in its preliminary instructions directed the jury that “there will be no testimony or any mention of injury. Any person mentioning injury or any medical treatment I direct you to disregard it.” This instruction was error and likely confused the jury. Defendant’s counsel objected to the court’s instruction and argued that causation was a necessary element of liability in negligence, that medical testimony concerning injuries would be required to prove proximate causation. Plaintiff’s counsel disagreed. He asserted that the parties, in a pre-trial conference before JHO Alfred Toker, agreed to limit the bifurcated trial to the issue whether there was a collision between the two vehicles. He further asserted that they had agreed that if the jury found that these two vehicles had collided, the defendant would tender the $25,000 policy without a trial on damages. The trial court referred this issue to JHO Toker for clarification. Upon clarification, the parties informed the trial court that medical proof would be introduced to prove proximate causation.
The preliminary instruction underscores the court’s own misapprehension, until trial commenced, regarding the scope of the agreement to bifurcate the trial. The court’s later instruction that “there may * * * be testimony concerning physical injury and treatment. If I allow that * * * you may consider it only as to the question of liability” likely did not dispel the confusion. In any event, plaintiff indicated for the record that at this stage of the trial, relevant and material medical testimony was unavailable on such short notice. Plaintiff was *392unable to call three treating physicians or subpoena defendant’s examining physicians. Plaintiff was able to call his treating neurologist, who testified concerning alleged exacerbation of back injuries, but not about some of the other alleged injuries.
This is not a case in which a fully developed record indicating the flaws in a plaintiff’s case warrants reinstatement of the verdict notwithstanding a faulty charge (cf., Califano v City of New York, 212 AD2d 146). Rather, it is a case in which “ ‘common sense, experience and [a] sense of fairness’ ” (Micallef v Miehle Co., 39 NY2d 376, 381 [citation omitted]) militate in favor of vacating that part of the verdict that necessarily depended on a fair exposition of medical proofs. Under the unique circumstances of this case, then, we exercise our interest of justice jurisdiction (CPLR 4404 [a]) to remand for a new trial on the limited issue of the nature and extent of the injuries and whether they were proximately caused by the accident. Concur — Rosenberger, Tom, Andrias and Wallach, JJ.