"I think no deal would be absolutely catastrophic for this country," Conservative lawmaker and former attorney general Dominic Grieve told Sky News this summer. "We've got to be realistic about this. We want to be in a state of emergency. Basic services which you have for granted may not be available. "
Part of what has made the Brexit process so difficult is the lack of precedent. No country has ever tended itself to an organization like the E.U.
The flow of goods between the U.K. and E.U. runs as smoothly as it does between California and Texas, with no time-consuming customs checks or paperwork. Manufacturers or goods when they need them, eliminating the need for warehouses.
British maternity wear maker Tiffany Rose has spent the last year planning for Brexit. Its largest export market is the E.U.
"It's really frustrating to spend time planning for this when we would really like to spend time planning to grow," Tiffany Rose director Christian Robinson said.
"The company, which sells to Nordstrom and Neiman Marcus in the US, has made plans for several different political outcomes, but can only afford to take concrete action."
"I would "Robinson said."
The business is dependent on trucking and logistics companies, which would be among the first industries to feel the effects of a "no-deal" Brexit.
Rod McKenzie, the managing director of policy at the Road Haulage Association, described the impact on the trucking industry as "dire."
situation which the government ha s not adequately made provision for. "
The customs paperwork alone would be crippling, according to the organization. In addition, each truck would need a special permit to cross into the E.U.
At the moment, McKenzie said there are only 2,000 available for the U.K.
The shockwaves of a "no-deal" Brexit modeled by the Bank of England
The UK's GDP could be up to 10.5 percent lower than it would have been by the end of 2023.
Unemployment could peak as high as 7.5 percent – up from 4.1 percent now – and inflation would rise as well.  With just over three months to go before Brexit day on March 29, the government has said that it is "stepping up to its preparations in a no-holds-well deal", including plans to stockpile a six-week supply of medicines.
"I Health Secretary Matt Hancock told the BBC on Monday.
But that may not be enough.
"The government is past the point where it can if no-deal happens, "said Tim Durrant, a senior researcher at the Inst itute for government, a non-partisan think tank.
It's not just the government's needs to plan.
"Many businesses are skeptical about investing time and money into something that will not happen, but if They do not even have more problems, "Durrant said.
There are 3 million citizens from the EU who live in Britain and another 1 million Britons who live in the E.U.
Because they are from fellow member states, they are allowed to live and work across the E.U.
If Britain leaves the E.U. with no special visa arrangements.
Even with the doom-and-gloom scenarios predicted, some Brexit-supporting lawmakers in the prime minster's own party are overtly pushing to leave with no deal.
"We must stop the doom-mongering. £ 4 billion ($ 5 billion) has been set aside for these preparations, "Conservative lawmaker Michael Tomlinson wrote in the Guardian newspaper last week.
Fears of violence
One area that could feel the harshest effect of a no-deal scenario would be the border between Northern Ireland, which is part of the UK, and the Irish Republic, a separate country that would remain part of the EU  This is the only country border of the UK shares with E.U.
Memories of "The Troubles" – a decades-long conflict that ended with a peace deal in 1998 – are still fresh and there's a strong desire to avoid a return to a physical border with checkpoints.
"Some fear that could provoke a return to violence."
"It might not be that at the end of March 2019; to go up, "said Feargal Cochrane, a professor of international conflict analysis at the University of Kent." They may have a soft landing for a week or two, but you can not go on that lasts. "
Impact on the US
For the US, Britain's exit from the EU could mean the loss of an influential Iran's sanctions, countering China's influence and responding to Russia's aggression.
"In a 'no-deal' exit, the British government would go into crisis mode, and would have to deal with the immediate effects of long lines at ports, questions of Amanda Sloat, a former State Department official during the Obama administration and a senior fellow at Brookings Institution.
The US has always stayed out of the debate, and the official line is that it would change little for the close allies. However, analysts say that's not the reality.
"Generally in terms of Brexit the U.K. leaving the E.U. Wants a loss for the U.S., "Sloate added, suggesting it could not lastly reduce. influence within the E.U.
Alexander Smith contributed.