LONDON, Aug 18 (Reuters) - British house prices rose in June at the fastest annual rate since 2004 as the market surged ahead of a phasing out of a tax break on property purchases, official data showed on Wednesday. House prices were 13.2% higher than in June 2020, the Office for National Statistics said, following a 9.8% annual increase in May. Finance minister Rishi Sunak cut stamp duty, a tax on house purchases, in July 2020. But from last month it started to return to its pre-pandemic level. The tax cut aimed to reverse a slump in property sales at the start of the pandemic, and helped fuel a surge in property prices and some new construction. Many households were already seeking more spacious housing suited to working from home. "Prices went berserk as the stamp duty taper closed in," said Lucy Pendleton from London-based estate agent James Pendleton. More timely gauges of the housing market suggest the market has cooled a little since June - but only a little. At the top end of the scale, house prices in the north west of England rose in June by 18.6% in annual terms, the ONS said. London stood at the bottom end but house prices there were still up 6.3%. Reporting by Andy Bruce; editing by James Davey Our Standards: The Thomson Reuters Trust Principles.