BP Plc reported the lowest quarterly profit in at least 10 years after a boom in trading faded and the conflict in Libya forced almost $600 million of writedowns. The weaker-than-expected results pile pressure on Chief Executive Officer Bob Dudley to cut capital spending to maintain dividends. The company is no longer benefiting from the strong trading that added about $350 million to profit in the first quarter, while a halt to operations in Libya eroded earnings from oil and gas exploration.