Ordinarily, any errors occurring during the course of trial in either a civil or criminal case can be addressed on appeal after entry of final judgment. However, there may be circumstances where an error is so egregious or so affects the trial that it cannot wait until the end of trial. In such cases, by statute and/or rule, an aggrieved party may seek relief before a single justice of the Appeals Court or Supreme Judicial Court.
In civil cases, the petition goes to a single justice of the Appeals Court pursuant to G.L. c. 231, § 118. A petition will not seek resolution of the entire case but will seek relief on an emergency basis from the problematic ruling. Section 118 typically will challenge the issuance or denial injunctive relief, but other emergency rulings in civil cases may be challenged. The single justice can decide the issue or can report it to the full bench of the Appeals Court for an interlocutory appeal.

In criminal cases and some civil cases, relief may be sought in the Supreme Judicial Court pursuant to G.L. c. 211, § 3. Again, relief may be sought for an egregious error made prior to the conclusion of trial. However, by statute, relief may not be granted unless the petitioning party has no other remedy, including the ordinary appellate process. While this is a difficult standard to meet, there are some circumstances where such petitions are allowed.

Where the trial court denies a motion to suppress evidence in a criminal case, a defendant has the right to petition a single justice of the Supreme Judicial Court pursuant to Mass. R. Crim. P. 15. “If the single justice determines that the administration of justice would be facilitated, the justice may grant that leave and may hear the appeal or may order it to the full Supreme Judicial Court or to the Appeals Court for determination.” Such relief is rarely granted, but in some cases may be worthwhile.