TOKYO -- When the U.K. announced uncosted tax breaks last year, it triggered a run on the sterling, sent British government bond yields to their highest since the global financial crisis, and hastened the downfall of Prime Minister Liz Truss after just 44 days in office. This year, the U.K.'s ratio of debt to gross domestic product surpassed 100% for the first time since the early 1960s.












