LONDON (AP) — One of Britain's leading mortgage providers says house prices in the country fell in December by their biggest amount in six and a half years, in a further sign that uncertainty surrounding Brexit is weighing on economic activity.

The Nationwide Building Society said Friday that house prices fell by a monthly rate of 0.7 percent in December, the biggest monthly decline since July 2012.

On an annual basis, prices were up only 0.5 percent, the lowest since February 2013.

The housing market, a barometer of the British economy, has slowed since the country voted in June 2016 to leave the European Union. Now that the country's actual departure in March is looming, the property market, like other sectors, is being hobbled by uncertainty over what Brexit will mean economically.