12.1 A restriction on jurisdiction as discussed in this chapter reflects the prohibition on bringing suit even though there is compliance with any general or specific jurisdiction base and the service of a claim form. The prohibition may go to the creation of jurisdiction in providing a further jurisdiction requirement, or it may go to the exercise of established jurisdiction. The distinction is probably of little practical significance save where the suit is at the court’s discretion and weight is given to the existence of jurisdiction apart from the discretion. The rules differ according to whether the substantive regimes of the EC Regulation 44/2001 or the Brussels or Lugano Convention apply.