In Spectra-Physics v. Superior Court (1988) 198 Cal.App.3d 1487, the Court agreed with the federal majority view that the deposition of opposing counsel is disfavored for public policy reasons and permitted only in very limited circumstances. (Spectra-Physics, supra, 198 Cal.App.3d at p. 1494.) Depositions of opposing counsel disrupt the adversarial system, have limited usefulness due to the attorney-client and work product privileges, add to the time and cost of litigation, detract from the quality of client representation because of the chilling effect on client communications, and also detract from counsel's ability to prepare the case. (Ibid.) This court in Spectra-Physics adopted the three-part test developed by the federal appeals court in Shelton, supra, 805 F.2d at page 1327, for determining the propriety of a deposition of opposing counsel. "The circumstances under which opposing counsel may be deposed are limited to those where: (1) no other means exist to obtain the information than to depose opposing counsel; (2) the information sought is relevant and not privileged; (3) the information is crucial to the preparation of the case." (Spectra-Physics, supra, 198 Cal.App.3d at pp. 1494, 1496.) In Spectra-Physics, the issue was whether "in preparing for a hearing to determine the good faith of a sliding scale settlement under Code of Civil Procedure section 877.6, the settling parties may depose counsel for the nonsettling defendants to inquire whether the nonsettling defendants may have been guilty of bad faith or unreasonable conduct . . . ." (Spectra-Physics, supra, 198 Cal.App.3d at p. 1490.) Applying the three-part test, this court ruled that the trial court had erred in permitting the depositions of opposing counsel because the proponent of the depositions had failed to meet its burden as to two prongs. (Id. at p. 1497.) The depositions of opposing counsel were not (1) necessary to gain information about the negotiations that had preceded the alleged bad faith settlement; or (2) crucial to the presentation of the deposition proponent's case. (Ibid.)