Reuters: BP Plc (BP.L) failed to reassure investors with a more than doubling of first-quarter net profits on Tuesday, as the oil major’s shares fell on growing fears about the impact of a worsening oil spill in the Gulf of Mexico. BP said replacement cost net profit, which strips out unrealized gains related to rises in the value of inventories, was $5.60 billion in the quarter, up from $2.39 billion in the same period of 2009, thanks to higher oil and gas prices. The underlying …