SECTION 1.  Chapter 279 of the General Laws, as appearing in the 2006 Official Edition, is hereby amended by inserting after section 4B the following section:—

Section 4C. The trial judge, in a district or superior court, upon his own motion or the written motion of a defendant filed within twenty-four months after the imposition of the sentence, within twenty-four months after receipt by the trial court of a rescript issued upon affirmance of the judgment or dismissal of the appeal, or within twenty-four months after entry of any order or judgment of an appellate court denying review of, or having the effect of upholding a judgment of conviction, may, upon such terms and conditions as he shall order, revise or revoke such sentence if it appears that justice may not have been done.