LONDON — Barely six months after Britain broke away from the European Union, Prime Minister Boris Johnson is increasingly consumed with trying to stop the breakaway of restive parts of the United Kingdom.
On Friday, Mr. Johnson sent his popular Treasury chief, Rishi Sunak, to Scotland, to tamp down nationalist sentiment that has surged there in recent months. Another top minister, Michael Gove, went to Northern Ireland with nearly $500 million in aid to help frustrated companies deal with new checks on shipped goods.
Experts have long predicted that Brexit would strengthen centrifugal forces that were pulling apart the union. But in Scotland, in particular, the coronavirus pandemic has accelerated those forces, forcing Mr. Johnson to mount an elaborate — some say belated — charm offensive with the Scottish public.
The situation is less acute in Northern Ireland, where reunification with the Republic of Ireland still seems a distant prospect. Yet businesspeople there, including those loyal to London, worry they will be hurt by a costly, bureaucratic trading system between Northern Ireland and the rest of the union.
Mr. Sunak, who as chancellor of the Exchequer is coordinating the British government’s economic rescue effort in response to the coronavirus, noted that 65,000 Scottish firms were getting 2 billion pounds ($2.6 billion) in loans to survive the lockdown. The pandemic, he said, had reaffirmed the enduring value of the union.
“If I look at the last few months, to me that is a good example of the union working really well,” Mr. Sunak said, after touring a factory in Glasgow that makes generators. He brushed aside questions about independence, saying, “I don’t think now is the time to be talking about these constitutional questions.”
The problem is: A majority of the Scottish public seems to disagree. In an average of recent polls, 52.5 percent of people say they would vote for Scottish independence. That is a dramatic swing from the 2014 referendum on independence, when Scots voted to stay in the union by 55.3 percent to 44.7 percent.
It is also the first time the polls have consistently shown a majority for breaking away, said John Curtice, a professor of politics at the University of Strathclyde and Britain’s leading expert on polling.
The numbers have clearly alarmed the government. Mr. Sunak is the fourth cabinet minister to visit Scotland in the last month — a list that has included Mr. Gove and the prime minister himself.
“The U.K. government is sufficiently worried that it is sending people north on a regular basis,” Professor Curtice said. “London may only have woken up to this in the last couple of weeks, but it’s a long-running story.”
Nationalist sentiment was already building last year, Professor Curtice said, as Britain hammered out a withdrawal agreement with the European Union. Scots voted overwhelmingly to stay in the European Union during the 2016 Brexit referendum.
Pro-independence feelings have hardened in Scotland during the pandemic because many people there believe that Scotland has done a better job managing the crisis than the Johnson government in neighboring England. England’s per capita death rate is higher than Scotland’s, and it continues to record more cases.
Under the terms of limited self-government in the United Kingdom, Scottish authorities are responsible for matters like public health, while the British government handles immigration, foreign policy and, importantly, Mr. Sunak’s rescue packages to protect those who lost their jobs in the lockdown.
Scotland’s overall performance during the pandemic is open to debate; it is far smaller and more sparsely populated than England. Some epidemiologists say it ranks in the middle of European countries in dealing with the virus.
Scotland’s first minister, Nicola Sturgeon, is far more popular in polls than Mr. Johnson, and her Scottish National Party stands to run up a huge mandate in parliamentary elections next May. That would make it harder for Mr. Johnson to refuse a Scottish demand to hold another referendum.
Political analysts said the Scottish National Party’s strategy has long been clear: to appeal to people who voted to remain in the United Kingdom in 2014, but also to stay in the European Union two years later.
“To wait until the polls shifted in Scotland was strikingly naïve,” said Anand Menon, a professor of European politics at Kings College London, referring to Mr. Johnson’s effort to woo the Scots. “The question is, whether this frantic activity is too little, too late.”
Mr. Gove, who holds the title of chancellor of the Duchy of Lancaster, faced a different dilemma in Northern Ireland. Britain’s withdrawal agreement from the European Union, analysts said, actually helped ease nationalist tensions because it preserved an open border between north and south on the island of Ireland.
But the deal came with a trade-off. Instead of bisecting Ireland, the border will effectively run up and down the Irish Sea. Northern Ireland, though part of the British customs territory, will adhere to a maze of European Union rules and regulations, which means goods shipped from England, Scotland and Wales will require customs checks.
Mr. Gove said the British government would pay £200 million ($260 million) to defray the cost of this paperwork for companies and £155 million ($202 million) for a new “light touch” technology system to streamline the process.
“I don’t accept the argument that there’s a border down the Irish Sea because Northern Ireland businesses, Northern Ireland people will continue to have totally unfettered access to the rest of the U.K,” Mr. Gove said during a visit on Friday to a carpet factory in Portadown.
His words, analysts said, were designed primarily to soothe unionists, who worry that Brexit will distance Northern Ireland from the rest of the United Kingdom and hasten its eventual reunification with the Irish republic. In assuaging the unionists, however, they said he would antagonize nationalists, whose emphasis is on fortifying Northern Ireland’s connection with the south.
“Michael Gove is a smooth talker, but nationalists wouldn’t believe a word that would come out of his mouth,” said Monica McWilliams, an academic and former politician in Belfast. “Those who voted against Brexit won’t be convinced by him, even if he is handing out pieces of candy.”
In a week shadowed by the death of John Hume, the Nobel Peace Prize-winner and architect of the Northern Irish peace process, the reunification of Ireland is not an immediate concern for Mr. Johnson’s Conservative government. But in both countries, the prime minister faces building pressures.
To some analysts, it exposes a contradiction at the heart of Mr. Johnson’s unrelenting drive to leave the European Union.
“You had a Brexit that took no account of the wishes of people in Scotland or Northern Ireland,” said Bobby McDonagh, a former Irish ambassador to Britain. “But that exists in parallel with a Conservative Party that celebrates the United Kingdom.”