Figures this week gave further indication of a slowdown in the pace at which property prices were rising. Prices had risen 11.7 per cent in a year, according to the Office for National Statistics, valuing the average property at £274,000. House prices in London were still rising faster than the rest of the country, increasing 19.6 per cent in 12 months, the ONS said. Its data followed a survey from Nationwide Building Society that indicated prices fell slightly in September.