Parts of Britain most in favour of leaving the European Union stand to hardest hit by Brexit, according to government impact studies.
The forecasts show the North East of England and the West Midlands, both areas where the majority backed the Leave vote, will see the largest economic slowdown.
Pro-Remain London will sustain the least economic damage after Britain's withdrawal from the EU, with growth slowing by between 1-2.5%.
The gloomy forecasts are likely to be seized upon by those calling for the UK to stay in the customs union and the single market, as Prime Minister Theresa May convenes her Brexit "war cabinet" for a second day on Thursday.
The documents show the North East could take a 11% hit to economic growth under the government's preferred outcome of a free trade deal with the EU.
Leaving the bloc with no deal would result in a 16% dip for the region's economy, while staying in the single market would see a less dramatic 3% decline.
A free trade deal would result in a 8% hit to growth in the West Midlands, compared with 13% under no deal.
If the UK stays in the single market, the area's growth would drop by 2.5%.
By comparison, a free trade deal would hit London's growth by just 2%, rising to 3.5% in a no deal scenario, and just 1% if the country stays in the single market.
The documents, prepared by the Department for Existing the EU, were released to MPs after they were leaked to the media last week.
They were to be read under controlled conditions, but the figures have been leaked.
Liberal Democrat Brexit spokesman Tom Brake said: "The government need to start being clear what they are fighting for. They are still keeping no deal on the table despite how crippling it would be to the regional economy.
"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."
Labour MP Stephen Doughty, a leading supporter of the pro-EU Open Britain campaign, said: "People in every corner of the United Kingdom will be shocked to see the government's own assessment of the damage Brexit will do to their communities."