The Administration of Justice Act 1956 is the current statute which sets forth the Admiralty jurisdiction of the High Court.1 It is the most recent of a line of statutory measures, dating back to the Admiralty Court Act 1840, which have been concerned with the consolidation and expansion of municipal Admiralty jurisdiction.2 The Act of 1956 continues in the tradition of its precursers but is also significantly distinct in that it is, in part, founded upon two international conventions. Namely, these are the International Convention Relating to the Arrest of Seagoing Ships, and the International Convention on Certain Rules concerning Civil Jurisdiction in Matters of Collision, both signed at Brussels on May 10, 1952.3 A principal purpose behind the enactment of the Administration of Justice Act 1956 was to give effect to the international legal obligations incurred by the United Kingdom Government under the terms of these Conventions.4

The aim of the International Convention Relating to the Arrest of Seagoing Ships was to harmonise, by the introduction of uniform rules, the varying in rem arrest procedures which prevailed among the major maritime nations.5 Broadly, the differences in the law and practice which had developed followed the two principal legal traditions in Western Europe. States within the civilian tradition tended to adopt a broad and liberal jurisdiction with a plaintiff entitled to arrest any property of the defendant within the territorial jurisdiction. In contrast, the Admiralty jurisdiction developed within the common law tradition was significantly more restrictive with the action in rem confined to the ship in respect of which the claim arose. Such was the well established principle of the Admiralty law of England.6 The Convention attempted to find a new harmony by adopting a middle-way compromise between the two approaches. Under the terms of the Convention the judicial arrest of a ship in respect of a maritime claim was confined to only one ship, but that ship might either be the ship in respect of which the claim arose or any other ship in the same ownership.7 It was this policy which the draftsmen of the Act of 1956 attempted to implement through the medium of s. 3(4). Although in international terms the policy was a compromise, it nonetheless represented, so far as the domestic Admiralty law of