An embargo on adequate food and medical aid can never be lawful, so those on board had the right to defend themselves. Daniel Machover’s Letter to the Times (UK) The attack by Israeli forces on the Turkish-registered vessel Mavi Marmara in international waters was clearly unlawful.

By virtue of the decision by the Permanent Court of International Justice in the Lotus case (1927), the basic principle under customary international law, is that “…vessels on the high seas are subject to no authority except that of the State whose flag they fly”; in this case, Turkey. Indeed, a 1988 treaty, to which Israel is a party, criminalizes the unlawful and intentional seizure or exercise of control over a ship by force and all connected injuries, deaths and/or detentions.

Israel claims that it was lawfully enforcing a legal blockade. Even if the blockade is legal, in order to rely on this legal justification, Israel is required to liaise with the flag state, Turkey, before trying to board the vessel. It did not.

In any event, this blockade is not lawful. An embargo on adequate food and medical aid can never be lawful. As the boarding of the Mavi Marmara by Israeli forces was unlawful, those on board had the right to defend themselves, subject to the constraints of Turkish criminal law. Any force used by Israeli commandos may be judged as unlawful, let alone the use of lethal force.

Turkey must now be assisted by all UN member states to gain access to all of the evidence relating to this incident so that it may conduct a comprehensive criminal investigation, at the conclusion of which the Israeli personnel involved may need to defend their actions before a criminal court. UN sanctions should be imposed against Israel if it refuses to co-operate with such an investigation. Finally, the unlawful blockade of Gaza must now end.

This letter to the editor by Daniel Machover, chair of Lawyers for Palestinian Human Rights, appeared in The Times (UK) on June 3, 2010