Britain's decision to leave the Europe Union is likely to lead to a net fiscal loss for the U.K. government's public finances, according to the head of an independent research institute.
"The forecast health of the public finances was downgraded by £15 billion ($20.25 billion) per year — or almost £300 million per week — as a direct result of the Brexit vote," said Carl Emmerson, deputy director of the Institute for Fiscal Studies in a letter to The Times of London newspaper published Tuesday.
"We are likely to make a net fiscal loss from it. Those are the numbers and forecasts which the government has adopted."
Emmerson's letter was in response to an article written by U.K. Foreign Secretary Boris Johnson at the weekend, which repeated the widely discredited and false claim that leaving the EU would free £350 million of spending per week.
The £350 million claim was used extensively by the leave campaign during the 2016 referendum on membership of the European Union. However, the figure does not take into account the rebate the U.K. receives, which instantly discounts the U.K.'s membership fee to around £250 million per week.
This £250 million is further reduced by payments from the EU to U.K. agriculture and poorer regions such as Wales and Cornwall, according to the independent fact checking charity Full Fact. The EU also makes further payments to the U.K. public sector, such as research grants.
"In 2014, these were worth an estimated £1 billion, so including them could reduce our net contribution further still," the Full Fact team says on its website.
"The money we get back will be spent on things the government may or may not choose to fund if we left the EU. It's not enough to look at the net contribution in isolation because what we get back isn't fully under our control."