The figure is worse than the 8.5 per cent cut to GDP growth predicted by a Scottish Government study last month.
Jude Kirton-Darling, Labour MEP for the North East of England, added: "As disquieting as this may be, it is unfortunately only the beginning of a string of very bad news to come out of the leaked impact assessment papers, and the direct result of the Tories being incapable of negotiating a Brexit deal that won't drain all money and economic prospects out of the North East".
London comes out the best with a drop of 1 percent in GDP growth staying in the single market, a drop of 2 percent under the trade-deal scenario, and a drop of 3.5 percent with no deal.
The Scottish Government has reacted with anger.
Likewise, it said a Brexit deal which maintained single market and customs union membership would cost 2.7% of Scotland's GDP, fractionally higher than Whitehall's assessment.
The Government's own analysis of the economic hit to GDP from a "no deal" Brexit would be 16% to North East England, Sky News can reveal.
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Northern Ireland would suffer an 8 per cent dip in growth after a free trade deal, a 12 per cent dip in the event of "no deal", and a 2.5 per cent fall in the single market.
Speaker John Bercow first ordered the papers to be released at the end of January, enabling MPs to be able to access them in a confidential reading room in Parliament.Since which time details have been leaked to the press. "People did not vote to make themselves poorer and should have the right to reject a bad deal on Brexit".
But officials said they did not show the impact of the Government's preferred post-Brexit option of an "unprecedented" economic partnership with the EU.
"The leak underlines the case that remaining in the single market and customs union is the only way to minimize that economic harm".
"A loss of growth of this magnitude will have a big impact on jobs and living standards".
The Liberal Democrat Brexit spokesman Tom Brake said: "This report confirms that every region and nation will be damaged by Brexit".
The series of measures are among those envisaged by Department of Health (DoH) officials at the latest meeting of the Oireachtas Joint Committee on Health held to consider the implications of Brexit on the health sector. The Tories are putting everything on the line because they do not care about the lives and livelihoods of the people of the North East. Download it today and continue to enjoy STV News wherever you are.