The gloomy chart showing the UK is already heading for recession

With the U.K. bracing for a downturn after the fallout from the Brexit vote last week, one chart highlights that the country may have already stumbled into an economic contraction.

Uncertainty over what deal the U.K. government could do with the EU has only replaced the uncertainty that businesses were initially facing from the vote itself. And with this concern looming over the economy the economic numbers trended lower as seen in the chart below.

Data firm Markit produces monthly surveys for manufacturing, construction and services sectors in the U.K. with all three indicators pointing to a downward move. A number below 50 marks a contraction in the sector with all three data points narrowly above that level in the May figures released on June 3.

Chris Williamson, the chief economist at Markit, said earlier this month that employment growth, backlogs of work and inflows of new business meanwhile all showed deteriorating trends.

"The manufacturing sector saw a near-stagnation of output growth for a second successive month in May, contrasting with robust growth earlier in the year. Growth has also slowed to a near-standstill in the construction sector," he said in the release.

"Although services growth accelerated slightly in May, the increase was still one of the weakest recorded in the past three years."

More analysis from the research firm showed how closely this PMI data mirrors GDP (gross domestic product) figures. A technical recession is generally identified by a fall in GDP in two successive quarters.

A manufacturing survey for June is due on Friday with a Reuters poll of 17 analysts predicting the sector will indeed show a contraction with a figure of 49.9.

"It seems almost inevitable that the heightened uncertainty created by the referendum will cause a further pull-back in business and consumer activity in coming months, raising the prospect of a likely contraction of the economy in the second half of the year," Williamson told CNBC via email on Wednesday.

"The degree to which this downturn extends into 2017 naturally depends on Brexit discussions between the U.K. and EU, but at the moment it seems hard to see an economy which is stuck in a state of limbo achieving any significant growth in 2017, paralyzed by uncertainty about the outlook."