President Trump’s newest trade threat sent markets into a frenzy once again on Friday. Earlier this week, Trump said he would back Republican proposals to halt exports of diesel in order to ease prices ahead of mid-term elections in November. US Treasury secretary Scott Bessent said there was a review underway of whether a ban could work as American diesel prices reached record highs at over £4.87 a gallon. Fuel prices could put Britain under threat. Reform UK’s Treasury spokesman Robert Jenrick reportedly wrote…