Dominic Cummings and Lee Cain will continue to work for the prime minister and Downing Street until mid-December, Number 10 has insisted.
Boris Johnson’s senior adviser was seen leaving No 10 carrying boxes on Friday evening amid reports he had quit his post with immediate effect.
Cummings and Cain, who resigned as communications chief, will still be employed until the middle of next month, although reports suggested Cummings would be working from home.
Sir Edward Lister was announced as the interim chief of staff pending a permanent appointment.
The news came amid a bitter power struggle in No10 over the past few days, which started with the resignation announcement by Cummings’ fellow Vote Leave veteran Cain on Wednesday.
Gavin Barwell, former chief of staff to then-prime minister Theresa May, said Cummings’ departure was a “big moment”.
He tweeted: “Boris now has an opportunity to get a more harmonious, effective Downing Street operation (like he had at City Hall); improve relations with the parliamentary party; and lead a less confrontational, more unifying government that better reflects his own character.”
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Shadow health secretary Jonathan Ashworth highlighted the strain being heaped on the NHS and the public by Covid-19 while “Downing Street is paralysed by the soap opera of these self-indulgent spin doctors,” adding: “It’s pathetic.”