This Practice Note provides a summary of the development of the ‘good arguable case’ requirement which will need to be met for the courts of England and Wales (English courts) to have jurisdiction to determine a claim. During the development of the requirement, it has been referred to in the authorities by a variety of different names: ‘good arguable case’, the ‘better argument’, or the ‘much the better argument’. In addition, the courts have applied glosses, explications and set out reformulations of the original requirement. The court’s approach to the evidence required to satisfy this test has also been the subject of much uncertainty with references to the need for evidence to be ‘reliable’, ‘clear and precise’, ‘plausible’, ‘sufficient’ or for the evidence to be of ‘real substance’. For guidance on the requirement and how it is to be met, see Practice Note: Cross-border service—‘good arguable case’ requirement. Origins of the ‘good arguable case’ requirement The leading modern case as to the meaning of ‘a good arguable case’ is the House of Lords decision