The British people will see their economy set back by nearly a decade. In the European Union, the economy will shrink by 1.5 per cent over the next decade. As for global gross domestic product (GDP) growth, already beset by a faltering Chinese economy and a protectionist US government, this will wind back to its slowest pace since 2009.
Such are the forecasts if, as expected, Britain's Parliament rejects Prime Minister Theresa May's Brexit agreement and the country crashes out of the EU with nothing but World Trade Organisation rules to govern its exports.
The forecasts, trickling in over recent months, reflect growing uncertainty among consumers and businesses as the prospect for what has been termed a no-deal Brexit looms larger as the March 29 deadline to reach a deal approaches.
That uncertainty will exacerbate volatility among emerging market currencies as investors yank investments from markets perceived as risky and park them in US dollar-dominated assets, said Mr Harry Su, managing director and head of equity capital markets at Samuel International in Jakarta.
A higher US dollar typically dampens commodity prices, the currency in which energy, metals and crops are typically priced, hitting big emerging economies such as Indonesia and Brazil as the biggest economies - the United States, the EU and China - struggle.
"It's going to create complexities and volatility at a time when global economies are slowing," Mr Su told The Straits Times, referring to a no-deal Brexit.
Earlier this month, the World Bank said US GDP growth would slow to 2.5 per cent, the slowest pace since 2009, when it contracted 1.7 per cent. China's economy will expand by 6.5 per cent, compared with 6.9 per cent last year. The EU will grow by 1.6 per cent, three percentage points slower than last year.
A no-deal Brexit could mean a Europe that becomes even more consumed with its own internal affairs, increasingly disengaged from global development.
DR MARTY NATALEGAWA, Indonesia's former foreign minister.
Last year, worries over budget deficits among emerging economies triggered a slump in their currencies, including Turkey's lira, the Philippine peso and the Indonesian rupiah. Investors parked billions in US dollar-denominated assets just as the US Federal Reserve was hiking interest rates.
Those currencies have recovered somewhat.
The rupiah, for example, has clawed back about 8 per cent of its value since November, helped in part by the central bank's five interest rate hikes since May. But the currency is still down 6 per cent from its level 12 months ago, in part because of a current account deficit that widened to 3.4 per cent during the three months ended September.
"A no-deal Brexit is going to be bad for Indonesia," Mr Su said.
The prospect of a no-deal Brexit is already bad for Britain.
In November, the International Monetary Fund said the British economy may eventually shrink by as much as 8 per cent should the country leave the EU without a deal, giving up hard-won gains after a decade when the GDP grew an average of 1 per cent a year following years of austerity.
While exporters have benefited from a cheaper British pound and benign interest rates, investment is on the wane. Business investment slowed from 2.4 per cent a year at the end of 2017 to 1.8 per cent a year, according to the most recent government data.
The uncertainty has carried over to British consumer confidence, UBS said in a research report yesterday. The investment bank's research shows that consumers have been consistently pessimistic about their outlook since before the 2016 referendum when British voters opted to leave the EU, UBS strategist John Wraith wrote in the report.
But outside of the immediate economic impact of a no-deal Brexit is the dismal prospect that the EU and Britain will be disengaged from world affairs and distracted by internal struggles at time when China and Russia are expanding their influence, said Dr Marty Natalegawa, Indonesia's former foreign minister.
"A no-deal Brexit could mean a Europe that becomes even more consumed with its own internal affairs, increasingly disengaged from global development," he told The Straits Times.
"At a critical juncture in regional and global developments, there is already a deficit of trust leadership and governance. This cannot be a welcome state of affairs," added Dr Marty.
Mr Wraith said that to be sure, there may eventually be a deal even if the vote fails. A badly divided Parliament will struggle to back any scenario, including a second referendum, or a deadline extension.
"Evidence of the withdrawal agreement's unpopularity is likely to be enough to win material concessions from the EU in our view, as avoidance of a disorderly exit is very important for their economic prospects, too."