The issue before the court was, in the words of the court,
19. … essentially, whether it is incompatible with Regulation No 44/2001 for a court of a Member State to make an order to restrain a person from commencing or continuing proceedings before the courts of another Member State on the ground that such proceedings would be contrary to an arbitration agreement, even though Article 1(2)(d) of the regulation excludes arbitration from the scope thereof
The ECJ answers that it is indeed incompatible:
It is incompatible with Council Regulation (EC) No 44/2001 of 22 December 2000 on jurisdiction and the recognition and enforcement of judgments in civil and commercial matters for a court of a Member State to make an order to restrain a person from commencing or continuing proceedings before the courts of another Member State on the ground that such proceedings would be contrary to an arbitration agreement.
In order to reach this conclusion, the Court offers a reasoning in two steps. First, the Regulation applies. Second, the Regulation excludes anti-suit injunctions.
Scope of Regulation 44/2001
This was arguably the key issue. The Regulation excludes arbitration from its scope. Yet, the Court finds that the Regulation still controls:
In that regard it must be borne in mind that, in order to determine whether a dispute falls within the scope of Regulation No 44/2001, reference must be made solely to the subject-matter of the proceedings (Rich, paragraph 26). More specifically, its place in the scope of Regulation No 44/2001 is determined by the nature of the rights which the proceedings in question serve to protect (Van Uden, paragraph 33).
Proceedings, such as those in the main proceedings, which lead to the making of an anti-suit injunction, cannot, therefore, come within the scope of Regulation No 44/2001.
However, even though proceedings do not come within the scope of Regulation No 44/2001, they may nevertheless have consequences which undermine its effectiveness, namely preventing the attainment of the objectives of unification of the rules of conflict of jurisdiction in civil and commercial matters and the free movement of decisions in those matters. This is so, inter alia, where such proceedings prevent a court of another Member State from exercising the jurisdiction conferred on it by Regulation No 44/2001.
It is therefore appropriate to consider whether the proceedings brought by Allianz and Generali against West Tankers before the Tribunale di Siracusa themselves come within the scope of Regulation No 44/2001 and then to ascertain the effects of the anti-suit injunction on those proceedings.
In that regard, the Court finds, as noted by the Advocate General in points 53 and 54 of her Opinion, that, if, because of the subject-matter of the dispute, that is, the nature of the rights to be protected in proceedings, such as a claim for damages, those proceedings come within the scope of Regulation No 44/2001, a preliminary issue concerning the applicability of an arbitration agreement, including in particular its validity, also comes within its scope of application. This finding is supported by paragraph 35 of the Report on the accession of the Hellenic Republic to the Convention of 27 September 1968 on Jurisdiction and the Enforcement of Judgments in Civil and Commercial Matters (OJ 1978 L 304, p. 36) (‘the Brussels Convention’), presented by Messrs Evrigenis and Kerameus (OJ 1986 C 298, p. 1). That paragraph states that the verification, as an incidental question, of the validity of an arbitration agreement which is cited by a litigant in order to contest the jurisdiction of the court before which he is being sued pursuant to the Brussels Convention, must be considered as falling within its scope.
Regulation 44/2001 excludes anti-suit injunctions
Once the Regulation was found applicable, it could certainly be expected, in the light of Turner, that the Court would not allow anti-suit injunctions:
It follows that the objection of lack of jurisdiction raised by West Tankers before the Tribunale di Siracusa on the basis of the existence of an arbitration agreement, including the question of the validity of that agreement, comes within the scope of Regulation No 44/2001 and that it is therefore exclusively for that court to rule on that objection and on its own jurisdiction, pursuant to Articles 1(2)(d) and 5(3) of that regulation.
Accordingly, the use of an anti-suit injunction to prevent a court of a Member State, which normally has jurisdiction to resolve a dispute under Article 5(3) of Regulation No 44/2001, from ruling, in accordance with Article 1(2)(d) of that regulation, on the very applicability of the regulation to the dispute brought before it necessarily amounts to stripping that court of the power to rule on its own jurisdiction under Regulation No 44/2001.
It follows, first, as noted by the Advocate General in point 57 of her Opinion, that an anti-suit injunction, such as that in the main proceedings, is contrary to the general principle which emerges from the case-law of the Court on the Brussels Convention, that every court seised itself determines, under the rules applicable to it, whether it has jurisdiction to resolve the dispute before it (see, to that effect, Gasser, paragraphs 48 and 49). It should be borne in mind in that regard that Regulation No 44/2001, apart from a few limited exceptions which are not relevant to the main proceedings, does not authorise the jurisdiction of a court of a Member State to be reviewed by a court in another Member State (Case C?351/89 Overseas Union Insurance and Others  ECR I-3317, paragraph 24, and Turner, paragraph 26). That jurisdiction is determined directly by the rules laid down by that regulation, including those relating to its scope of application. Thus in no case is a court of one Member State in a better position to determine whether the court of another Member State has jurisdiction (OverseasUnion Insurance and Others, paragraph 23, and Gasser, paragraph 48).
Further, in obstructing the court of another Member State in the exercise of the powers conferred on it by Regulation No 44/2001, namely to decide, on the basis of the rules defining the material scope of that regulation, including Article 1(2)(d) thereof, whether that regulation is applicable, such an anti-suit injunction also runs counter to the trust which the Member States accord to one another’s legal systems and judicial institutions and on which the system of jurisdiction under Regulation No 44/2001 is based (see, to that effect, Turner, paragraph 24).
Lastly, if, by means of an anti-suit injunction, the Tribunale di Siracusa were prevented from examining itself the preliminary issue of the validity or the applicability of the arbitration agreement, a party could avoid the proceedings merely by relying on that agreement and the applicant, which considers that the agreement is void, inoperative or incapable of being performed, would thus be barred from access to the court before which it brought proceedings under Article 5(3) of Regulation No 44/2001 and would therefore be deprived of a form of judicial protection to which it is entitled.
Consequently, an anti-suit injunction, such as that in the main proceedings, is not compatible with Regulation No 44/2001.