Boris Johnson Becomes U.K. Prime Minister, Replacing Theresa May

Philip Hammond, the chancellor of the Exchequer; David Gauke, the justice secretary; Rory Stewart, international development secretary; and David Lidington, the de facto deputy prime minister — had all said they would refuse to serve in a Johnson cabinet, and all were among a dozen people who resigned, or ended up being fired, over Mr. Johnson’s accession.

Meanwhile, the opposition parties were not very impressed by Mr. Johnson’s enthusiastic promises.

“Boris Johnson is about to learn that there is a massive gulf between glib throwaway lines that delight the Tory faithful and the difficult decisions of leadership,” Keir Starmer, who is responsible for Labour’s Brexit policy, said on Twitter.

And Nicola Sturgeon, leader of the Scottish National Party and first minister of Scotland, which is pro-Europe and anti-Brexit, posted a tweet: “Behind all the ‘make Britain great again’ type rhetoric, that speech was rambling, blame-shifting and, to put it mildly, somewhat divorced from reality.’”

In Europe, Mr. Johnson has been an unpopular figure ever since his days as a young journalist writing inaccurate articles portraying Europe as a wasteful, bloated bureaucracy determined to do things like enforce one-size-fits-all condoms. Nor did he make many friends as foreign secretary under Mrs. May, or in recent months as he maneuvered to become prime minister and increased the volume of his anti-Europe rhetoric.

“We look forward to hearing what the new prime minister, Boris Johnson, wants,” Michel Barnier, the European Union’s chief Brexit negotiator, told the BBC Wednesday. “Is it an orderly Brexit, which is the choice or the preference of the E.U.?”