The practice of imposing economic sanctions in order to influence the actions of states and other parties—historically with varied levels of actual effectiveness—has a long and chequered history.2 Given, however, that more than 90 per cent of the world's trade is carried by sea,3 it is one particular form of sanction management—the ‘so called economic weapon’ of naval blockade— which tends to dominate the implementation of sanctions regimes.4 Yet despite the frequency with which naval forces are used to implement maritime sanctions—or perhaps because of the long but erratic history of naval embargo and blockade—the regime as a whole remains haunted by some uncertainties as to its conceptual basis. As WL Martin observes, ‘some measures such as “pacific blockade”, have at times acquired a technical meaning’ which has left them ill-equipped to deal with and adjust to new developments in blockade practice.5 Even prior to 1914, the notion of ‘blockade’ was a dualist concept. On one hand, it was clearly a weapon of war.6