Order unanimously affirmed with costs. Memorandum: Sixteen months after filing a trial note of issue, defendant moved to be relieved of its failure to serve and file a timely demand for jury trial (see, CPLR 4102). Defendant failed to demonstrate factually that failure to demand a jury trial was inadvertent or unintentional and failed to assert any excuse for its delay in seeking relief. Under the circumstances, the trial court’s denial of defendant’s motion was not an abuse of discretion (see, Green v Siben, 104 AD2d 923; Keller v Keller, 66 AD2d 960).

We also conclude that the court did not abuse its discretion in severing the third-party action and directing a separate trial of that claim. The third-party action was asserted three years after commencement of the main action, one year after the main action reached the Trial Calendar, and on the eve of trial. No excuse was proffered for the delay in commencing the third-party action, and the court properly concluded that plaintiff would be unduly prejudiced by further delays in trial of the main action (see, Strange v Sampson, 73 AD2d 749; Vita Food Prods, v Epstein & Sons, 52 AD2d 522). (Appeal from order of Supreme Court, Oswego County, Hurlbutt, J. — jury trial.) Present — Callahan, J. P., Denman, Pine, Balio and Lawton, JJ.