Donald Trump was on a fresh collision course with the Ukrainian president, Volodymyr Zelenskyy, and European allies on Friday after a stunning agreement to buy Russian diesel, upending years of US and western pressure on the Kremlin to end its four-and-a-half year war against Ukraine. Zelenskyy reacted furiously to Trump’s announcement of the deal with President Vladimir Putin of Russia, calling it “absolutely terrible” and “not fair and not honest”. Zelenskyy, who told Axios that it “looks like a happy birthday present for Putin. It looks absolutely terrible.” The Russian leader turned 74 earlier this week. In a long social...