U.K. 30-year government bond yields surged to their highest level in nearly 30 years after Greater Manchester Mayor Andy Burnham launched a direct leadership challenge to Prime Minister Keir Starmer. The yield on the 30-year gilt jumped 16 basis points to 5.821% as international investment funds liquidated British government debt, fearing an unhedged, high-spending fiscal pivot under a potential Burnham premiership. The political turmoil overshadowed a benign inflation print, with the consumer price index holding flat at 2.8% for the 12 months through May, defying forecasts of an energy-driven spike and giving the Bank of England room to keep its benchmark rate steady at 3.75%. Burnham confirmed his candidacy for the Makerfield by-election, positioning himself to trigger a formal Labour leadership contest, while former Health Secretary Wes Streeting indicated readiness to launch a rival bid. The gilt market rout reflects a structural shift in which opportunistic international hedge funds now dominate trading, demanding punitive yields amid policy uncertainty.