Matters of procedure are governed by the lex fori, English law, whatever be the lex causae, for example, the French governing law of a contract. Whether a question is procedural or substantive has presented difficulties of classification, as has the question of whether a foreign rule of law affects procedure or substance. It is easy enough to state that substantive issues are those which concern the existence of a right whereas procedural issues are those which concern the method and means of enforcement of a right. But acute difficulties may be encountered in deciding whether even an English rule is procedural or substantive. Thus, in Chaplin v. Boys the majority of the House of Lords regarded the question whether a victim of the tort of negligence could recover damages for pain and suffering as concerned with remoteness of damage, whereas the minority appeared to think that it was a question of quantification of damages. Remoteness is a question of substance, quantification one of procedure.

Matters have been made worse by the almost inveterate habit of English judges of classifying questions and rules of law as procedural, so leading them to apply English law. In one context the result led to such difficulties that Parliament intervened.

In what follows, three topics will be discussed in some detail: (a) evidence, (b) limitation of actions and (c) remedies. Two others, (d) priorities and (e) parties to an action, will be mentioned briefly.