Part of the fascination of the law of the sea is the way in which – despite major technological change – similar problems are faced, and familiar legal concepts deployed, over generations and even centuries. This is true of many of the issues addressed so adeptly by Douglas Guilfoyle in his work on interdiction of foreign ships at sea. We have piracy still with us, a subject dealt with in more detail by the 1982 Law of the Sea Convention than maritime delimitation. We have the old law of hot pursuit adapted to expanded maritime zones. We have The Lotus, which concerned jurisdiction to prescribe not to enforce, but which stipulated, a fortiori, a flag-state monopoly of high seas enforcement which constitutes the main challenge for those concerned to interdict suspect ships or cargos at sea.

At the same time, facing the relatively simple and well-known jurisdictional rules for high seas interdiction in time of ‘peace’ we have a range of old and new challenges to international and national law – people smuggling as well as drug smuggling, illicit fisheries, the suspected transport of weapons of mass destruction or of strategically interdicted cargos, and so on. Some of these problems may be transient – like the ‘pirate radio stations’ of the 1960s. Others are perennial.

As Guilfoyle shows, underlying every lawful interdiction there must be jurisdiction not only to enforce by the very act of boarding and inspection but also to enforce through prosecution and confiscation, disposal or return.