That alone is unlikely to be enough to satisfy the 27 other member nations, but Mrs. May will no doubt hope that the opening bid is good enough to revive talks, particularly if her rhetoric is as constructive as the government has hinted it will be.
According to excerpts from the speech released by her office, Mrs. May will say that while Britain’s departure “is inevitably a difficult process, it is in all of our interests for our negotiations to succeed.”
“If we can do that,” she is expected to say, “then when this chapter of our European history is written, it will be remembered not for the differences we faced, but for the vision we showed.”
European Union negotiators have refused to talk about post-Brexit ties until they judge that there is “sufficient progress” on the issues they consider a priority: the status of European Union citizens in Britain after it leaves, the border between Ireland and Northern Ireland (which is a part of the United Kingdom) and Britain’s financial commitments to the bloc.
“From the European Union’s point of view, it probably takes us 50 percent of the way there,” said Mats Persson, who was a special adviser to former Prime Minister David Cameron and is now head of international trade at the advisory firm EY. “It’s moving us forward, but whether it constitutes ‘significant progress’ for the E.U., I am just not sure.”
Mrs. May briefed her cabinet about plans for the speech on Thursday, after a tense week in which divisions were paraded in public, with Boris Johnson, the foreign secretary and a hard-line proponent of a withdrawal, publishing a 4,000 word essay outlining his vision of the future.
The episode illustrated how the referendum last year on withdrawal, intended to end the Conservative Party’s divisions over Europe, only sharpened them. To make matters worse, senior ministers are jockeying to succeed Mrs. May, who made a huge tactical mistake by calling a general election in June, in which her party lost its parliamentary majority.
Mr. Johnson attended the two-and-a-half-hour meeting, after dismissing reports that he might resign. In a public show of unity, he emerged after the meeting alongside the chancellor of the Exchequer, Philip Hammond, who has led calls for a “softer” departure from the bloc that could afford greater protections for the economy.
Only hours earlier, Mrs. May’s former chief of staff, Nick Timothy, who supports leaving the bloc, published an article in The Daily Telegraph asserting that Mr. Hammond’s department was reluctant even to “mention the positives” of leaving the European Union, and accusing the chancellor of being on “maneuvers” to replace Mrs. May.
Mrs. May was expected to use her transition statement to calm anxieties in the business world while also reassuring withdrawal hard-liners that, when the initial phase is over, Britain would not be bound by the bloc’s economic, migration and legal rules.
The European Union’s chief negotiator, Michel Barnier, said on Thursday that there was still significant “uncertainty” over Britain’s position, and that time was of the essence if a deal is to be reaching.
Noting that six months had passed since Mrs. May set withdrawal negotiations in motion, and arguing that six months would be needed to allow for ratification of any agreement, Mr. Barnier said, “There is therefore only one year left.”
Mrs. May’s speech was being criticized in Britain even before she spoke. Peter Bone, a Conservative lawmaker and supporter of leaving the bloc, said that the reported terms of her financial offer were unacceptable.
The money that “Theresa May is reportedly about to offer as the biggest divorce settlement in history would simply be the down payment,” said Vince Cable, leader of the centrist Liberal Democrats, which opposes a withdrawal. “Brexit will cost a lot, lot more than this.”