In hindsight, some said, the conference might be seen as a high-water mark for the prime minister.
“A few days of disruption to fuel supplies makes the government look foolish,” said Jonathan Portes, a professor of economics and public policy at King’s College London. “Much larger fuel bills are a much bigger deal.”
Tim Bale, a professor of politics at Queen Mary, University of London, said Mr. Johnson could come to resemble James Callaghan, the Labour prime minister who was toppled in 1979 after a winter of fuel shortages and runaway inflation, when he did not appear sufficiently alarmed about the pileup of problems.
When Mr. Johnson bounded into the auditorium at the conference last week, stopping to kiss his wife, Carrie, he looked anything but alarmed. Between jokes and jibes at the opposition, he presented a blueprint for a post-Brexit economy that he claimed would deliver high wages for skilled British workers, rather than lower-cost immigrants from the European Union, and put the onus on businesses to foot the bill.
Companies and previous governments “reached for the same old lever of uncontrolled immigration to keep wages low,” Mr. Johnson said. “The answer is to control immigration, to allow people of talent to come to this country, but not to use immigration as an excuse for failure to invest in people, in skills and in the equipment, the facilities, the machinery they need to do their jobs.”
That model is worlds away from Singapore-on-Thames, the catchphrase once used by the intellectual authors of Brexit to describe an open, lightly regulated, business-friendly hub that they said Britain would become once it cast off the labor laws and other shackles of Brussels. Nobody is talking about removing labor laws now (indeed, Mr. Johnson may soon move to raise Britain’s minimum wage).