When does the Supreme Court exercise its power of granting special leave?

* In civil cases, the Supreme Court does not grant appeal unless it involves a substantial question of law of general importance. * In criminal cases, the Supreme Court only grants appeal when the circumstances are special and exceptional and grave injustice has been done. * If a tribunal delivers a judgement which is in excess of their jurisdiction or undemocratic or against the principles of natural justice, then the Supreme Court can quash the judgement.