Britain's economy grew by 0.1% in the July-to-September period of this year, the Office for National Statistics said on Monday, in line with its initial estimate.Economists polled by Reuters had forecast the reading for gross domestic product would be unrevised.Growth in the second quarter was revised down to 0.2% from a previous estimate of 0.3%, the Office for National Statistics said.Last week the Bank of England said it expected zero GDP growth in the October-to-December period but it thought that the underlying pace of economic growth was around 0.2% per quarter.Monday's data showed that Britain's GDP in the third quarter was 1.3% higher than a year ago - unchanged from the ONS's initial estimate - while on a per capita basis, output was 0.9% higher