LONDON (Reuters) - Retail sales were flat on the month in August against expectations for a small rise, with clothing sales exerting the biggest downward impact, official data showed on Thursday 17 September.

Analysts had predicted a 0.1 percent rise on the month and the Office for National Statistics said August's unchanged reading took the annual rate of growth in retail sales volumes down to 2.1 percent from 2.9 percent in July.

In addition, July's previously reported monthly gain of 0.4 percent was revised down to a rise of 0.2 percent.

The figures are unlikely to alter expectations that the Bank of England will keep policy ultra-loose for some time to come. The central bank last week held interest rates at a record low of 0.5 percent and said it would keep its 175 billion pound asset-purchase programme in place.

Despite last month's weak outturn, sales in the three months to August rose 1.2 percent, the biggest increase since May 2008.

The official measure of retail sales has been unusually resilient for much of this year, surprising analysts who had predicted much weaker outturns given Britain is in the midst of its worst recession in decades.

Survey evidence, however, has been much weaker, leading analysts to question the accuracy of the official data, particularly as retailers themselves have been complaining of lacklustre demand and being forced to cut prices aggressively.

In August, however, the ONS said prices were on average only 0.4 percent lower than a year ago, having been 0.7 percent down on the year in July.

The ONS said the biggest upward impact on monthly sales volumes came from food stores, while non-food sales, particularly clothing, was down. Textile, clothing and footwear sales fell 1.3 percent on the month.