Jacob Rees-Mogg exposed a "major flaw" in the Treasury's recent Brexit forecast, which he claims makes the document "worthless." The Brexiteer MP pointed out global trends have not been modeled in the report. Speaking in the House of Commons, Mr Rees-Mogg said: "I am sure my honored friend recalls the wild inaccuracy of the Treasury's forecasts before the referendum results, Brexit punishment and an increase in unemployment of 800,000. But there is no major flaw in the document we have before us, in that global trends have not been modeled, yet it is believed that 90 percent of future global economic growth will come from outside the European Union?
"And without thinking that this forecast is worthless."
To which Mel Stride, Financial Secretary to the Treasury, replied: "I can make two points to the Honorable Gentleman.
"The first is that this is not a Treasury report as such, it has involved as I have just outlined, discussions and involvement right across the entire Government.
"Then as to the issue of future trade deals, he will find a buried within the detail that in fact assumptions have been made about future trade deals with countries such as the United States, China and India.
The comments come from analyzes produced by across Whitehall's departments, says the UK will be economically worse off after Brexit, regardless of whether Theresa May's deal is supported or the country leaves with no divorce deal from the EU.
Withdrawal from the EU under the Government's plans could cut UK GDP by up 3.9 percent over the next 15 years, according to the new figures.
But leaving without a deal could deliver a 9.3 percent hit to GDP over the same period.
The document did not put a cash figure on the potential impact on the economy, but independent experts have said that 3.9 percent of GDP would equate to around £ 100 billion a year by the 2030s, far outweighing the current UK's contribution to the EU budget.
Meanwhile, the Long-Term Economic Analysis paper found that Government borrowing could be forced up by as much as £ 119 billion by 2035 if the UK left the EU without a deal and up to £ 26.6 billion under a scenario similar to the plans of Mrs. May.
The 83-page document was drawn up by officials from Whitehall departments including the Treasury, the Department for Exiting the EU, Industry, Environment, International Trade and the Home Office.
Chancellor Philip Hammond acknowledged that all possible Brexit options will make Britain economically poorer, compared with remaining in the EU.
But he insisted that the Prime Minister's plan – agreed by EU leaders at the Brussels summit last Sunday – will "minimize" the economic damage.