In Fiona Trust & Holding Corp v Privalov,1 the House of Lords signalled a new dawn in the common law of jurisdiction clauses and arbitration agreements. Some hideous old authorities and patterns of reasoning were consigned to the bin, and a more practical, less abstracted, approach took centre stage. Five years on, however, it is clear that some real puzzles remain, and that litigation about whether the parties have agreed where to litigate is still the daily business of the Commercial Court. The flow of new cases and new arguments shows little sign of slowing; it is timely to examine some of them. Of course, many of the issues with which this paper is concerned may be dismissed as raising nothing more interesting than a question of construction. That would be thoughtless, not least because there really is nothing more interesting than a question of construction.

Questions of scope, validity and effect are many and varied. The tangled issues may appear more clearly if the problems are broken down into six connected, common law points. Taken together, these allow it to be determined whether a jurisdiction clause is intrinsically valid and applicable to the matter in dispute. They also lay the basis for showing why the Brussels I Regulation is so different. Of course, the question whether a jurisdiction clause, which is valid according to its own terms, will be given effect to establish the jurisdiction of a court, or to remove the jurisdiction of a court, or to provide a basis for other relief, will also depend on the laws of the forum, which may limit the legal effect of the agreement which the parties have made. Even though the law on the