Oil prices have plunged to the lowest level this year as US shale producers boost output at an astonishing pace and crude inventories keep rising, triggering a wave of selling by hedge funds with record speculative positions. The US surge threatens to neutralise cuts agreed by the Opec cartel and a Russia-led group of producers last November, potentially delaying a full recovery of the market until 2018 or even later. Texas light crude fell to $48.90 a barrel on Thursday after yet another surprise jump in US stocks. Prices have slid 8pc in three days and have broken through key levels of technical support, dousing enthusiasm for commodities across the board. Higher interest rates are expected to push up the value of the dollar and suck in foreign funds to the US financial system. Surveys show firms are concerned that the high dollar will dent exports, and Trump has accused China and rival exporting nations of winning trade wars after artificially depressing their currencies.