Interdiction of ships suspected of being engaged in human trafficking
The fact that doubts exist whether the right to interdict under Article 110(1)(b) UNCLOS is applicable to human trafficking and/or migrant smuggling raises the question whether any other international agreement provides for a right to intervene to be given to non-flag states. As stated above, if applied only between the states parties to the agreement, such a right would be perfectly compatible with Article 110(1) UNCLOS, taking into account that this provision contains an express reservation concerning acts of interference deriving from powers conferred by treaty. While numerous treaties exist that address the issues of human trafficking and smuggling of migrants, the most important of which are the First and the Second Protocol to the UNTOC and the United Nations Convention for the Suppression of the Traffic in Persons and of the Exploitation of the Prostitution of Others^ none of these agreements assigns any specific intervention rights to non-flag states. In particular, the Second Protocol to the UNTOC, dedicated, inter alia, to the Smuggling of Migrants by Sea, does not authorize non-flag states to interdict and board vessels suspected of being engaged in human trafficking, or migrant smuggling, without the consent of the flag state. The general duty to cooperate with non-flag-state enforcement contained in Article 7 is substantiated by Article 8(2), which states that:
[a] State Party that has reasonable grounds to suspect that a vessel exercising freedom of navigation in accordance with international law and flying the flag or displaying the marks of registry of another State Party is engaged in the smuggling of migrants by sea may so notify the flag State, request confirmation of registry and, if confirmed, request authorization from the flag State to take appropriate measures with regard to that vessel. The flag State may authorize the requesting State, inter alia: (a) to board the vessel; (b) to search the vessel; and (c) if evidence is found that the vessel is engaged in the smuggling of migrants by sea, to take appropriate measures with respect to the vessel and persons and cargo on board, as authorized
by the flag State.
Paragraphs 3 to 6 of Article 8, and Article 9, of the Second Protocol to the UNTOC prescribe further safeguards in favour of the flag state, the most important one being that ‘[a] State Party shall take no additional measures without the express authorisation of the flag State, except those necessary to relieve imminent danger to the lives of persons or those which derive from relevant bilateral or multilateral agreements’.™! Thus, apart from the possibility of concluding bilateral agreements, international law does not envisage autonomous rights for non-flag states to interdict ships suspected of human trafficking or the smuggling of migrants.
-  Italics added. 101 Art. 8(5)(2) Second Protocol to the UNCTOC. 102 Probably the first agreement in this regard was the Convention between the United Kingdom and theUnited States of America Respecting the Regulation of the Liquor Traffic of 23 January 1924, UKTS No. 22. This treaty was the result of a dispute between the USA and the UK regarding the lawfulness of USmeasures taken against ships that were suspected of smuggling rum, but that were situated in internationalwaters. While the USA claimed to protect its national interests, the UK regarded these activities as being inclear violation of international law. By concluding the treaty, the UK agreed not to protest against the boarding of ships flying the British flag outside the territorial waters of the USA where these ships were suspectedof being engaged in liquor smuggling. Cf. Guilfoyle, Shipping Interdiction, cited in note 10 above, p. 81.юз Geifi and Tams, ‘Non-flag states as guardians’, cited in note 36 above, p. 35.