May suggests she is prepared to demote Boris Johnson

The prime minster said she would not "hide from the challenge" when asked about the foreign secretary, who has infuriated colleagues by interventions on Brexit that triggered questions of leadership.

Her comments, after a nightmare conference speech that she admitted was "uncomfortable", were backed up by the Conservative leader in Scotland, Ruth Davidson, who warned: "People serve in cabinet entirely at the pleasure of the prime minister." Davidson stressed that Johnson had made a public show of loyalty, but urged May to ensure that the foreign secretary was true to his word. "He has come out this week to say he is fully behind every dot, comma, and word of the Florence speech," Davidson told the BBC's Andrew Marr Show. "I want to see the prime minister hold him to that."

Davidson described Johnson as a "big intellect and big figure in the party", adding that the prime minister had her support if she believed he was the best person to be foreign secretary.

But in a warning that appeared to be aimed both at cabinet members and Grant Shapps—whose attempted coup fizzled out after a backlash from colleagues – Davidson claimed colleagues had forgotten that they were lucky to be serving the country. "It is not and should never be about private ambition."

She added that "lying in wait [is Jeremy Corbyn's] neo-Marxist government ready to take over". In further signs of angst within the party between the most ardent Brexit supporters and those who campaigned for remain, the Tory MP Nadine Dorries told ITV's Peston on Sunday she believed it was wrong to focus on Johnson.