ON MOTION FOR REHEARING
Reynolds-Penland contends that the trial court erred because the question of its failure to timely exercise its option constituted an “honest and justifiable mistake” was a question for the trier of fact rather than a matter that can be determined by the court on summary judgment. Additionally, it asserts that whether the delay is slight, the loss to the lessor small, and whether the denial of the relief would result in such a hardship to the tenant as to make it unconscionable to enforce literally the time requirement for exercising the op*246tion in the lease are questions for a jury. We cannot agree. These ultimate determinations which trigger the interposition of equity are made by the court, not the jury. To permit a jury to determine these issues is to permit it to determine whether equitable relief should be granted. This is impermissible in our system. Jones v. English, 268 S.W.2d 686, 690 (Tex.Civ.App. — San Antonio 1954), aff’d, 154 Tex. 132, 274 S.W.2d 666 (1955). The question of whether equity ought to intervene must be determined by the court based upon all of the circumstances of the case and the principles of equity, with which a jury is not presumed to be familiar. Bergstedt v. Bender, 222 S.W. 547, 549 (Tex.Com.App. — 1920, judgmt. approved); Fabra v. Fabra, 221 S.W. 1008, 1009 (Tex.Civ.App. — San Antonio 1920, writ ref’d); Bourland v. Huffhines, 269 S.W. 184, 186 (Tex.Civ.App.— Amarillo 1925), aff’d, 280 S.W. 561 (1926).
In the case at bar, it was, therefore, the court’s function to determine whether established facts authorized equitable intervention to override the explicit agreement of the parties. It has similarly been held that a jury cannot determine issues such as whether a city ordinance is reasonable, City of Austin v. Austin City Cemetery Ass’n, 87 Tex. 330, 28 S.W. 528, 531 (1894), or the “issue of expediency, necessity or propriety of equitable relief.” Alamo Title Co. v. San Antonio Bar Association, 360 S.W.2d 814, 816 (Tex.Civ.App.—Waco 1962, writ ref’d n. r. e.); Codgell v. Fort Worth National Bank, 544 S.W.2d 825, 829 (Tex.Civ.App.— Eastland 1976, writ ref’d n. r. e.). See Dennis v. United States, 341 U.S. 494, 71 S.Ct. 857, 869, 95 L.Ed. 1137 (1951). Cf. Hanson Southwest Corp. v. Dal-Mac Construction Co., 554 S.W.2d 712, 717 (Tex.Civ.App.—Dallas 1977, writ ref’d n. r. e.) (holding that whether one corporation is the alter ego of a parent is not a jury question).
Although we agree with the dissent that the right to a jury trial extends to disputed fact issues in equitable, as well as legal proceedings, we cannot agree that such questions as whether the delay is slight or whether an unconscionable hardship results are the type of disputed fact issues that may be decided by a jury. A jury could, of course, determine facts such as when the notice to renew was given or the value of the improvements made by either the tenant or the landlord. Our holding is simply that a jury may not determine the ultimate grounds mandating equitable intervention.
Reynolds-Penland seeks to draw a distinction between the exercise of discretion by a trial court in a plenary trial and on motion for summary judgment. In so doing, the dissent, as well as Reynolds-Penland, would have us remand this case on the ground that the trial court could not exercise its discretion on motion for summary judgment where the facts are undisputed. In our view, Reynolds-Penland’s position places form above substance and would be an unwarranted waste of judicial time. In Elias v. Manis, 292 S.W.2d 836, 838 (Tex.Civ.App.—Beaumont 1956, writ ref’d), that court held, in a well-reasoned opinion, that summary judgment may be granted upon the application of equitable principles to undisputed facts.
Consequently, even assuming such a rule as enunciated in F. B. Fountain to be the rule in Texas, we would, nevertheless, hold that the trial court did not abuse its discretion in declining to grant relief. Whether an unconscionable hardship will result or whether the failure to exercise the option was the result of an “honest and justifiable mistake” so as to justify the interposition of equity are matters within the sound discretion of the trial court, subject, of course, to an abuse of discretion standard of review. Mathews v. First Citizens Bank, 374 S.W.2d 794, 797 (Tex.Civ. App.—Dallas 1963, writ ref’d n. r. e.). See Annot., 27 A.L.R. 981, 982 (1922). Since the trial court did not abuse its discretion, the motion for rehearing is denied.