British inflation unexpectedly slowed last month and core measures of price growth - tracked by the Bank of England - fell more sharply, according to official data that will be welcomed by finance minister Rachel Reeves after recent a market selloff. The annual rate of inflation eased to 2.5% in December from 2.6% in November, the Office for National Statistics said. Economists polled by Reuters had mostly expected a headline inflation reading of 2.6%. The BoE - which will announce its next interest rate decision on Feb. 6 - forecast in early November that inflation would be 2.5% in December.