Russian interference with them there would be an act of war, against Nato member nations. So grain ships could leave Odesa and hug the coast going south, where they would remain within the territorial waters of Romania, Bulgaria and Turkey. And indeed the British intelligence update has it that the only Russian vessel so far to take up a blockade-like position, the corvette Sergey Kotov, is patrolling well to the south. The Black Sea Fleet would probably not care to operate close in to the Ukrainian coast: the fate of the missile cruiser Moskva, sunk by Ukrainian missiles last April, illustrated the dangers of doing this. Grain ships need to travel between Ukrainian ports, the main one being Odesa, to the Bosporus strait in Turkey and so gain access to the world’s oceans via the Sea of Marmara and the Aegean. The most obvious impact of this would be to interdict Ukrainian grain exports: Russia recently withdrew from an agreement under which it was permitting such exports to continue, and has been hitting Ukrainian ports and grain storage facilities with missile strikes. British military intelligence reported yesterday that Russia’s Black Sea fleet may be planning a naval blockade of Ukraine, in which it might intercept and seize merchant vessels travelling to and from the embattled nation.

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