Britain would face shortages of fuel, food and medicine if it leaves the European Union without a transition deal, jamming ports and requiring a hard border in Ireland, according to government documents leaked to The Sunday Times of London, a scenario Brexit opponents have long warned about.
The forecasts compiled by the Cabinet Office set out the most likely aftershocks of a no-deal Brexit rather than the worst-case scenarios, the newspaper said.
Up to 85 percent of trucks using the main channel crossings “may not be ready” for French customs, meaning disruption at ports would potentially last up to three months before the flow of traffic improves, the documents suggest, according to the British news outlet.
The files show that the government also believed that a hard border between Northern Ireland, which is part of Britain, and Ireland, which will remain a European Union member state, would be most likely since current plans to avoid widespread checks would prove unsustainable, the report said.
“Compiled this month by the Cabinet Office under the code name Operation Yellowhammer, the dossier offers a rare glimpse into the covert planning being carried out by the government to avert a catastrophic collapse in the nation’s infrastructure,” the newspaper reported.
“The file, marked ‘official sensitive’ — requiring security clearance on a ‘need to know’ basis — is remarkable because it gives the most comprehensive assessment of the UK’s readiness for a no-deal Brexit.”
Prime Minister Boris Johnson’s office told the newspaper that it did not comment on leaked documents.
But on Sunday Kwasi Kwarteng, a junior energy minister, dismissed concerns over potential food, fuel and drug shortages.
“I think there’s a lot of scaremongering around and a lot of people are playing into ‘Project Fear,’ ” he told Sky News when asked about the leaked government document. “We’ve got to prepare for no deal. We will be fully prepared to leave without a deal on Oct. 31.”
The report also said Gibraltar, the semiautonomous British territory on Spain’s southern coast, would face hourslong delays at the border with Spain “for at least a few months,” affecting its economy. In a statement on Sunday, the government of the territory called the report “out of date” and “based on planning for worst-case scenarios which the government of Gibraltar has already dealt with.”
The plans related to the flow of people, vehicles and goods across the frontier, especially foodstuffs, medicines and waste, it said.
Fabian Picardo, Gibraltar’s chief minister, added: “We do not want a no-deal Brexit. We think it is bad for Gibraltar. We are, nonetheless, now ready for it.”
Analysts say that Britain is heading toward a constitutional crisis at home and a showdown in Brussels as Mr. Johnson has repeatedly vowed to leave European Union by the current deadline, Oct. 31, without a deal unless it agrees to renegotiate the Brexit divorce. This week, he heads to Europe for his first official foreign trip as prime minister to meet with President Emmanuel Macron of France and Chancellor Angela Merkel of Germany to make his case.
Mr. Johnson planned to tell Mr. Macron and Ms. Merkel that Westminster cannot stop Brexit and that a new deal must be agreed if Britain is to avoid leaving without one.
After more than three years of Brexit dominating European affairs, negotiators in Brussels have repeatedly refused to reopen the withdrawal agreement, which includes an Irish border insurance policy that Mr. Johnson’s predecessor, Theresa May, agreed to in November.
Britain’s Brexit Secretary, Stephen Barclay, said on Twitter on Sunday that he had signed legislation that set in stone the repeal of the 1972 European Communities act, the laws that made Britain a member of the organization now known as the European Union.
Though his move was largely procedural, in line with previously approved laws, Mr. Barclay said in a statement: “This is a clear signal to the people of this country that there is no turning back.”
A group of more than 100 lawmakers have written to Mr. Johnson calling for an emergency recall of Parliament to discuss the situation.
“We face a national emergency, and Parliament must now be recalled in August and sit permanently until Oct. 31 so that the voices of the people can be heard, and that there can be proper scrutiny of your government,” the letter said.
The prime minister is coming under pressure from politicians across the political spectrum to prevent a disorderly departure, with the leader of the opposition Labour Party, Jeremy Corbyn, vowing this week to bring down Mr. Johnson’s government in early September to delay Brexit.
It is, however, unclear if lawmakers have the unity or power to use Parliament to prevent a no-deal departure, likely to be Britain’s most significant move since World War II.
Opponents of no deal say it would be a disaster for what was once one of the West’s most stable democracies. A disorderly divorce, they say, would hurt global growth, send shock waves through financial markets and weaken London’s claim to be the world’s pre-eminent financial center.
Brexit supporters say there may be short-term disruption from a no-deal exit but that the economy will thrive if cut free from what they cast as a doomed experiment in integration that has led to Europe falling behind China and the United States.