Order and judgment (one paper), Supreme Court, New York County (Carol Arber, J.), entered February 8, 1995, which granted the motion of loft tenant Conley for leave to intervene, and for dismissal of the proceeding on the grounds of lack of prosecution and gross laches, unanimously affirmed, with costs.
The IAS Court’s determination that the tenant was an interested person in this CPLR article 78 proceeding that could affect his leasehold was within its "sound discretion” (Matter of White v Incorporated Vil. of Plandome Manor, 190 AD2d 854, lv denied 83 NY2d 752; CPLR 7802 [d]). Petitioner’s decade-long delay constitutes laches, warranting dismissal (see, Matter of Diggins v New York City Fire Dept. Arts. 1 & 1B Pension Funds, 183 AD2d 422, lv denied 80 NY2d 760). We have considered petitioner’s remaining arguments and find them to be without merit. Concur — Sullivan, J. P., Ellerin, Rubin and Tom, JJ.