Without insurance, no ships sail. That's why, at number 1 Lime Street, in the heart of the City of London, Donald Trump's words have a relative impact. He can say one thing or the opposite. Or that the war will end in "the next two or three weeks", after sending Iran "to the stone age, where it belongs." Or that the navy's aircraft carriers will protect the passage of oil tankers through the Strait of Hormuz. Or even more: that it will be the Western allies who will have to do it, either by warlike or diplomatic means, such as those discussed on Thursday by the thirty-five countries that, with the United Kingdom as host, met virtually to analyze the alternatives to the blockade of oil flow in the Persian Gulf.