Ordered that the order is affirmed insofar as appealed from, with costs.
While it is firmly established that leave to amend a pleading shall be freely granted ( see, CPLR 3025 [b]), a motion to amend is committed to the broad discretion of the Supreme Court, and its determination will not lightly be set aside ( see, Citrin v Royal Ins. Co., 172 AD2d 795; Napoli v Canada Dry Bottling Co., 166 AD2d 696). In this case the defendant third-party plaintiff sought leave to amend its bill of particulars in the third-party action nine years after the occurrence which caused the plaintiffs injuries, five years after the third-party complaint was filed, and one year after the third-party defendant filed a note of issue. The defendant third-party plaintiff has failed to support its motion with an affidavit showing the merit of the proposed amendment or an affidavit showing a reasonable excuse for the extensive delay from the time it was first made aware of the facts upon which the proposed amendment is predicated. The defendant third-party plaintiff has also asserted a new theory of liability based on different factual aspects of the underlying incident, and there is a possibility that evidence has been lost in the interim. Under the circumstances, it was not an improvident exercise of the court's discretion to deny the defendant third-party plaintiffs motion for leave to amend its bill of particulars ( see, Allen v Vuley, 223 AD2d 868; Scott v General Motors Corp., 202 AD2d 570; Alexander v Seligman, 131 AD2d 528; Beuschel v Malm, 114 AD2d 569).