Britain's decision to leave the European Union has had a profound impact on the world's fifth largest economy, but recent data suggests not all of the influences have been negative, leaving investors with a series of uncertainties in the months ahead.

U.K. retail sales growth slowed to 0.9% last month, data from the country's biggest industry lobby group showed Tuesday, as shoppers trimmed non-essential spending in favor of food purchases. The British Retail Consortium, which publishes the data along with KPMG, said food sales rose 2.3% in the three months ending in July, compared to a 0.7% gain in non-food spending.

"The month's growth was underpinned by food sales alone, while non-food sales relapsed into negative territory as the competition heats up over a shrinking pool of discretionary consumer spending power," the BRC said.

Consumer spending, one of the most important drivers of U.K. growth last year, slowed significantly over the first six months of this year as Britons pulled back on non-essential spending amid a surge in prices, a fall in the pound on foreign exchange markets and flat domestic wage growth.

"Consumption is projected to remain subdued in coming quarters, as real income growth remains weak and households continue to adjust to past falls in their purchasing power," the Bank of England noted in its recent assessment of the British economy, in which it trimmed its forecasts for growth both this year and next. "The pace at which households moderate their spending in response will be a key determinant of the outlook for overall GDP growth."

However, Brexit has also created a curious paradox in Britain's labor market, which the number of permanent roles increased at the fastest pace in more than two years last month, according to the Recruitment and Employment Confederation, while official data has the country's unemployment rate at the lowest level since the 1970s.

"Recruitment agencies signalled a sustained and marked increase in demand for staff," the REC said. "Furthermore, overall demand for staff rose at its joint-strongest pace for 23 months."

On top of that, UK factory output rose at the strongest pace in 12 years over the three months ending in July, according to the Confederation of British Industry, and although it comprises only a small portion of the nation's GDP, it is nonetheless an important contributor to broader investor and consumer confidence.

And that, it seems, is an area that could use some support: market research group GfK's benchmark reading of U.K. consumer optimism hit a one-year low of -12 last month, while the household assessment of the current economic situation slumped to its lowest level in four years.

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The mixed picture of the country's post-Brexit fortunes are evident in the way in which the pound has gained more than 4.2% against the U.S. dollar since Prime Minister Theresa May called a snap election on April 18 -- one that eventually cost her a majority in parliament and appears to have weakened the government's negotiating position with Brussels -- as investors bet on a "softer" EU exit that could include a longer transition period under the current arrangement.

In fact, a recent ORB opinion poll, published Monday, showed that nearly two-thirds of British voters disagree with May's approach to Brexit, a view that's changed markedly since her snap election decision in April.

"This months Brexit tracker suggests the damage from a poor election result is continuing to cast doubt over Brexit," said ORB managing director Johnny Heald. "Confidence that the prime minister will be able to negotiate the right deal remains brittle."

Given the strength of the European recovery -- second quarter GDP estimates suggest the Eurozone economy is growing at its fastest annual pace in six years -- and the pound's 15.5% fall against the single currency since the June 2016 referendum, any extension of the country's trade ties with the EU could boost U.K. growth and employment even as domestic spending continues to flat-line.

That could make any immediate Brexit assessment even more difficult that it has already become.

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