the court noted that this immunity from jurisdiction of a foreign national court, existed even when foreign national courts exercise an extended criminal jurisdiction on the basis of various international conventions that covered the prevention and punishment of certain serious crimes. however the court emphasized that "while jurisdictional immunity is procedural in nature, criminal responsibility is a question of substantive law. jurisdictional immunity may well bar prosecution for a certain period or for certain offences; it cannot exonerate the person to whom it applies from all criminal responsibility."