W and another v X C-499/15, [2017] All ER (D) 180 (Feb)
The Court of Justice of the European Union gave a preliminary ruling deciding that Art 8 of Regulation (EC) No 2201/2003 and Art 3 of Regulation (EC) No 4/2009 should be interpreted as meaning that, in a case such as that in the main proceedings, the courts of the member state which had made a decision that had become final concerning parental responsibility and maintenance obligations with regard to a minor child no longer had jurisdiction to decide on an application for variation of the provisions ordered in that decision, inasmuch as the habitual residence of the child was in another member state. It was the courts of the member state of habitual residence that had jurisdiction to decide on that application.