—Judgment, Supreme Court, New York County (James Leff, J.), rendered on June 28, 1989, convicting defendant, on his plea of guilty, of robbery in the second degree, and sentencing him to a term of imprisonment of from 8 years to life, unanimously affirmed.
Having pleaded guilty to robbing a man on a subway, defendant requested at sentencing that his plea be withdrawn and that new counsel be provided. The trial court was within its discretion in refusing to vacate the plea, as no cognizable ground to withdraw the plea, which was knowing and voluntary, had been advanced. (People v Stubbs, 110 AD2d 725, 727-728.) It was not necessary for the court to inquire into the validity of a prior conviction which had already served as a basis for an enhanced punishment, from which no appeal had been taken. Concur—Sullivan, J. P., Milonas, Ross, Kassal and Rubin, JJ.