In People v. Drake (61 N.Y.2d 359 [1984]), the Court of Appeals held that the failure to impose sentence "without unreasonable delay" causes the court to lose jurisdiction and requires that the charges must be dismissed. Moreover, the Court held that the existence of an unreasonable delay absolves the defendant of having to demonstrate actual prejudice from the delay to be entitled to dismissal of the charges: "the New York rule assumes the defendant has been prejudiced by unreasonable delay He need not prove it." (Id. at 367.) The reasonableness of a delay depends not only on the length of the delay but the explanation for the delay. (Id. at 366.) Delays caused by legal proceedings or the defendant's efforts to frustrate the entry of judgment are excusable and ordinarily will not be classified as unreasonable. (Id.) Delays caused by judicial or prosecutorial neglect or mistake are different; those delays are inexcusable and will be found unreasonable. (Id.)