LONDON (Reuters) - British house prices rose at their fastest annual pace in four months in July, in data that might not yet reflect any impact from June’s vote to leave the European Union, mortgage lender Nationwide said on Thursday.

A row of houses are seen in London, Britain June 3, 2015. REUTERS/Suzanne Plunkett/File Photo - RTSJU71

“The outlook for the housing market remains unusually uncertain and it may take several months for the underlying trends in the market to become evident,” Nationwide economist Robert Gardner said.

Nationwide said house prices rose 5.2 percent in July compared, edging up from 5.1 percent in June. Economists polled by Reuters had expected house prices to rise 4.5 percent.

In monthly terms, house prices rose by 0.5 percent, from 0.2 percent in June.

Nationwide said its figures might not yet capture any impact from the June 23 Brexit vote. Its data is based on property prices at the time when buyers are offered mortgages, something which occurs with a short lag after a decision to buy a property.

A fall in consumer confidence since the referendum might be a sign of weakness to come in the housing market but prices could hold up if sellers decide to take their properties off the market, Gardner said.

It was also likely that property transactions would slow over the summer after a rush to buy rental properties and second homes before a new tax was introduced in April.

“Determining how much of any fall-back in activity is the result of the tax changes and how much is due to the referendum will be difficult,” Gardner said.

Earlier this month, the Royal Institution of Chartered Surveyors said uncertainty caused by the Brexit vote prompted a “marked drop” in housing market activity.

RICS said separately on Thursday that growth in construction orders has also slowed after the referendum.