The FTSE 100 edged lower for a third straight session as investors weighed softer U.S. inflation data, which reinforced expectations that the Federal Reserve will keep rates unchanged next month, against persistent Middle East tensions that lifted oil prices and damped risk appetite. London shares were pressured by major oil and pharmaceutical names, with Shell and BP each down more than 1%, AstraZeneca falling 1.5%, GSK losing 2.1% and Unilever slipping more than 1%. Tesco dropped more than 2% after Shore Capital downgraded the retailer to hold. Brent crude stayed elevated as uncertainty over the Strait of Hormuz persisted, while tougher U.S. rhetoric on Iran, including threats to maintain a naval blockade indefinitely and further measures aimed at the "economic isolation" of Iran, added to market caution.