If the government is defeated in the vote at 10pm on Monday evening it would likely trigger a general election.
But it would take a significant number of Conservative MPs to rebel for it to pass and this is not expected to happen, despite the party having moved to oust the prime minister as leader.
Opening the Commons debate, Johnson delivered a lengthy defence of his time in office, with a focus on Brexit, the Covid vaccine rollout and support for Ukraine in its war against Russia.
Turning to the Tory leadership contest, he said: “After three dynamic and exhilarating years in the cockpit, we will find a new leader and we will coalesce in loyalty around him or her.
“And the vast twin Rolls-Royce engines of our Tory message, our Conservative values, will roar on – strong public services on the left, and a dynamic free market enterprise economy on the right, each boosting the other and developing trillions of pounds of thrust.”
But Starmer said Johnson’s “delusions” he “fostered in his bunker” were “never ending”.
“What a relief for the country that they finally got around to sacking him,” the Labour leader told the PM.
“He’s been forced out in disgrace,” Starmer said. “They’re sacking him because he’s untrustworthy.”
Johnson is set to remain as prime minister until the Conservative Party elects a new leader on September 5.
Starmer, who had initially demanded the vote of no confidence before the government tabled it itself, said every day Tory MPs allowed Johnson to remain in office was a “dereliction of duty”.
“This is not the summer for Downing Street to be occupied by a vengeful squatter mired in scandal,” he said.
“Why are they leaving him with his hands on the levers of power for eight weeks?
“Eight weeks where Britain will be represented abroad by someone who has lost all respect at home.
“Eight weeks of a caretaker government led by an utterly careless prime minister.”
It came as Tory MPs voted in the latest ballot in the party’s leadership contest.
Whoever comes last out of Rishi Sunak, Liz Truss, Penny Mordaunt, Kemi Badenoch and Tom Tugendhat will be eliminated from the contest.
Tugendhat is seen as likely to be knocked out when the result is announced at 8pm on Monday.