«When separation proceedings are taking place in a Member State other than where the child is not habitually resident, the best interests of the child and the proximity criterion, as provided by whereas 12 and 13 of Brussels II a Regulation, require a separate assessment of the two issues and not to give jurisdiction on parental responsibility to the judge seised with the matrimonial proceedings, unless this has been agreed with the defendant spouse and is not contrary to the best interests of the child».
This point, undisputed by legal literature and compliant with the Regulation, is still facing some resistance in the Italian judicial practice. It has been however been reaffirmed by the Supreme Court with the decision n. 17676 of the 7th of September 2016 (see the original document). 
The dispute concerns an Italian husband and his English wife. The couple got married in Italy in 2009. After the marriage, the woman went to live in the UK where the son of the couple was born. A short time later, the man applied to the Court of Torre Annunziata (Naples) for separation. The judge declared his jurisdiction on separation pursuant to Article 3 of the Reg. n. 2201/2003 and also on the custody of the child, despite the fact that he had habitual residence in England.
The mother issued proceedings for custody of her son before the Court of Dartford (UK) and at the same time challenged the decision of the court of Torre Annunziata before the Court of Appeal of Naples.
In May 2013 the Court of Appeal of Naples upheld the appeal of the woman, and declared the jurisdiction of the English court both on the separation and the parental responsibility according to Articles. 3, 8 and 12 of that Regulation.
Against that decision, the man appealed to the Italian Supreme Court (Corte di Cassazione).
According to the Supreme Court – which has rightly denied a request for referring a preliminary ruling to the European Court of Justice on the relationship between Article 3 and 8 Reg. – the correct application of the Regulation confers jurisdiction on separation proceedings to the Italian court and jurisdiction on parental responsibility proceedings to the English court. Such a conclusion is grounded on the best interest of the child and on the criterion of proximity. In fact, the jurisdiction on the custody of the child can be attracted within the jurisdiction of the court for matrimonial proceedings only when a) there is an agreement of the spouses and b) this is in the interests of the child. Both these conditions were not met in this case. (See: Italian Supreme Court No 30646/2011)
The Court also notes that the court in charge of parental responsibility will also have jurisdiction over issues on maintenance of the minor, since these are ancillary to custody (Italian SC n. 5418/2016; n. 16648/2014; ECJ judgment of 9 October 2014 C 374/14, judgment of 22 December 2010 C 497/10, judgment of 2 April 2009 C 523/07).
On the other hand, once the proceedings in matrimonial matters are pending, these cannot be removed on the assumption of a vis actractiva of the different proceedings on parental responsibility brought before the English court. The principles of perpetuatio jurisdictionis and of lis pendens oppose to such a result and preclude that jurisdiction shifts in favour of a proceeding that was subsequently started abroad (even if connected to the first one (On this subject see: Italian SC. No 5710/2014)
In conclusion, the Italian Supreme Court declared the jurisdiction of the Italian courts in the proceedings of separation of the spouses, and the lack Italian jurisdiction over proceedings on custody and child support.
Valentina Vadacca