British house prices rose at an annual rate of 12.2 percent in May, the fastest rate so far this year and up from 10.0 percent in April, official data showed on Monday. The Office of the Deputy Prime Minister said the average non-seasonally adjusted house price stood at 170,719 pounds ($317,600) in May. The figures are in line with an acceleration in house prices in May shown by surveys from mortgage lenders the Halifax and Nationwide Building Society, although these surveys put house price inflation at an annual rate of around 20 percent. More recent data from Halifax and the Nationwide have suggested house price inflation may have moderated in June. House prices are closely watched by Bank of England policy-makers who have expressed concern about runaway house price inflation.///