Reference procedure for validity questions allows higher determination and permits interim custody or bail during pending decision. A trial court that finds adjudication of the validity of an Act, Ordinance, Regulation or provision necessary and believes it to be invalid must state a case with reasons and refer it to the higher court. 'Regulation' is as defined in the General Clauses Act. A Court of Session may also, where the mandatory reference does not apply, refer questions of law arising in a case. Pending the higher court's decision on any such reference, the referring court may either commit the accused to custody or release them on bail to secure appearance.