Boris Johnson has begun assembling his new cabinet, with several senior Conservatives leaving their government jobs.
Penny Mordaunt, Liam Fox, Greg Clark, Chris Grayling, Damian Hinds, Karen Bradley, David Mundell and James Brokenshire have all returned to the backbenches.
And in a shock move, Foreign Secretary Jeremy Hunt said he was returning to the backbenches.
Speaking outside Downing Street, Johnson said he would take the UK out of EU by October 31 “no ifs, no buts” and hit out at “pessimists”.
“The doubters, the doomsters, the gloomsters, they are going to get it wrong again,” he said.
“I will take personal responsibility for the change I want to see. “Never mind the backstop, the buck stops here.”
Several senior Conservatives, including chancellor Philip Hammond, resigned from the government rather than wait for Johnson to fire them.
A source close to Johnson the new prime minister would “build a cabinet showcasing all the talents within the party that truly reflect modern Britain”.
Theresa May used her farewell statement to say Johnson’s priority must be a Brexit “that works for the whole United Kingdom”.
Hunt was forced from his role and his supporters were rounded on by the freshly-anointed Tory leader.
Johnson sacked Liam Fox as international trade secretary and Penny Mordaunt as defence secretary, PA understands.
Fox and Mordaunt had backed Hunt, while Fox had gone a step further in criticising Johnson’s Brexit plan.
Scottish Secretary David Mundell, who previously said he would find it “extremely difficult” to serve Johnson, tweeted that he was “disappointed but not surprised” to be departing.
Also leaving the frontbenches after Johnson was formally appointed as PM by the Queen were Hunt-backer Hinds and Business Secretary Greg Clark.
Clark had recently warned that “many thousands” of jobs would be lost in a no-deal Brexit, which Johnson has declined to rule out.