The Whitehall numbers are similar to those put out by the Scottish Government, which said a no-deal scenario would result in an 8.5 per cent hit for Scotland's growth after 15 years.
Pro-Remain London will sustain the least economic damage after Britain's withdrawal from the European Union, according to the controversial forecasts.
The potential impact on automotive manufacturers could cause concerns as Mrs May prepares to host a meeting with Japanese business leaders on Thursday - including representatives from the country's motor industry.
Yet after MPs were given the detailed figures to read under controlled conditions, they were swiftly leaked and suggest that for Scotland the loss to growth under the three scenarios - single market membership, trade deal or no deal - would be 2.5 per cent, six per cent and nine per cent respectively.
The UK government had argued that releasing the analysis to the public could damage its negotiations with the EU.
Banks Nomura, Daiwa Securities and Sumitomo Mitsui Financial Group have London bases but have already chose to set up operations in Europe to retain access to the single market as they await clarity on future trading arrangements.
Leave-voting Wales would suffer a 9.5 percent drop in GDP growth under a no-deal scenario, with Remain-backing Scotland facing a fall of 9 percent and Northern Ireland down by 12 percent.
However, Michael Russell, the Scottish Government's Brexit Minister, threatened to make them public, saying voters had a right to know about the Brexit impact.
'The Government need to start being clear what they are fighting for.
In another warning, Britain-based banks looking to maintain their access to the eurozone after Brexit have been told they are running out of time to apply for licences and should not count on a deal about a transition period, according to European Central Bank board member Sabine Lautenschlaeger.
"People did not vote to make themselves poorer". They should be allowed a vote on the final deal and a chance to exit from Brexit'.
"However, this is but the first step to clarity about what Brexit means for our European Union citizenship", he said in a statement.
She told MPs: 'As I have said right from the very beginning we will hear noises off, we will hear all sorts of things being said about positions that are being taken. We've shown we can do that.
A spokesman added: "As Ministers clearly set out in the House, this is provisional internal analysis, part of a broad ongoing programme of analysis, and further work is in progress".
'We are seeking an unprecedented, comprehensive and ambitious economic partnership - one that works for all parts of the UK.
Online Sports Betting Market Growth
Benefits With the market high, sports betting is an activity that receives a high level of support from online betting companies. More betters are opting to forego the long lines at the cashier's counter and the unavailability of their favorite machines.
LSU lands Chase and Joseph but loses out Surtain Jr
The Tigers could certainly use Beal's size and athleticism, but there are already five scholarship tight ends on the roster. Another LSU target, James Foster, a 4-star dual quarterback from Montgomery, AL, signed with Texas A&M.
Celebrities Who Suffer With Chronic Diseases
Now if that isn’t the epitome of what a BFF is, I don’t know what is! Selena continues to be on chronic medication. There is also a huge list of celebrities past like famous painter vincent Van Gogh who suffered with this disease.