London's FTSE 100 fell for a second consecutive session, with the blue-chip index dropping 2.7%, marking its steepest one-day fall in nearly a year. The Office for Budget Responsibility is expected to lower its forecast for economic growth this year, while British finance minister Rachel Reeves is likely to maintain her promise to address the public finances in a budget update speech later in the day. Concerns over the U.S.-Israeli war on Iran could increase inflationary pressures.