Labour has opened up a remarkable 15-point lead in the polls as chaos continues to engulf the Tories.
Boris Johnson was forced to resign last week over his handling of the Chris Pincher scandal.
More than 50 MPs had quit his administration by the time he decided to throw the towel in.
Health secretary Sajid Javid and chancellor Rishi Sunak were among them, with three education secretaries appointed in three days.
Johnson also faced growing calls from senior Tories to hand over to a caretaker prime minister rather than wait for a permanent successor to be elected.
Former prime minister Sir John Major said it would be “unwise and may be unsustainable” to allow Mr Johnson to stay on for a prolonged period in which he would continue to be able to wield considerable power.
“Some will argue that his new Cabinet will restrain him. I merely note that his previous Cabinet did not – or could not – do so,” he said.
Polling released on the back of the turbulent events showed Labour has opened up a 15-point lead over the Conservatives.
Mike Galsworthy said “this is freefall we are looking at now” in response to the results.