Energy firms provided a rare pocket of strength, with UK sector shares rising 1.6% as the regional impasse effectively stalled hopes for a diplomatic breakthrough between the U.S. and Iran. This geopolitical friction is already bleeding into the domestic economy; an S&P Global survey revealed a contraction in British services activity during May, driven by rising costs and waning business optimism.

Market participants are now bracing for the Bank of England's June 18 announcement, with LSEG data indicating a 90% probability that borrowing costs will remain unchanged at 3.75%. Corporate results painted a disparate picture: while Bridgepoint Group tumbled 9.8% following withdrawal caps at a major fund, and Ninety One shares fell 4.6% on lackluster inflows, retail performers defied the broader slump. B&M shares surged 16.1% after reporting a smaller-than-expected profit decline, and Debenhams Group climbed 14.4% on the back of a return to growth in its first-quarter merchandise value.