“She’s like a really old Jeep, making its way slowly through a rutted field,” said Anand Menon, a professor of European politics and foreign affairs at King’s College London. “You keep thinking that it’s going to break down, but it inches forward and just keeps on going.”

For her conference speech, Mrs. May entered with some dance steps to the sound of Abba’s “Dancing Queen,” a self-deprecating reference to headlines she made with an awkward performance in Kenya in August. Then she joked about last year’s conference speech disaster, telling the audience that if she coughed this year, it was only because she had been up all night fixing the letters to the backdrop.

Then it was on to Britain’s exit from the bloc, or Brexit. Mrs. May is scheduled to meet European leaders again this month, and told her party that she would be entering “the toughest phase of the negotiations.”

With a growing campaign for a second referendum on withdrawal, Mrs. May warned hard-line Euroskeptic critics, “If we all go off in different directions in pursuit of our own visions of the perfect Brexit, we risk ending up with no Brexit at all.”