Theresa May is to carry out a Cabinet reshuffle on Monday with reports that a series of senior ministers are set for the axe.
The Prime Minister has been forced to make changes to her top team following the resignation last month of Damian Green as first secretary of state after he admitted to lying about the alleged discovery of pornographic images on his Commons computer during a police raid.
But unlike the previous resignations of Sir Michael Fallon and Priti Patel - when consequent changes were kept to a minimum - his departure is expected to trigger a wider ministerial re-jig.
Downing Street sources indicated that it would continue into a second day on Tuesday with the middle-ranking and junior ministerial appointments.
Mrs May's most senior colleagues - including Chancellor Philip Hammond, Foreign Secretary Boris Johnson, Home Secretary Amber Rudd and Brexit Secretary David Davis - were reported to be safe.
However Education Secretary Justine Greening, Conservative Party chairman Sir Patrick McLoughlin, Business Secretary Greg Clark and the Leader of the Commons Andrea Leadsom were among those said to be vulnerable.
The Sunday Telegraph reported that Ms Greening was fighting to hold on to her position, posting a series of tweets highlighting her achievements in the education brief, twice declaring "school standards are rising".
Downing Street sources sought to play down the reports describing them as "speculation" and "guesswork".
It is thought that Mrs May will take the opportunity to bring forward some more junior ministers, with Immigration Minister Brandon Lewis and Justice Minister Dominic Raab among those tipped for promotion.
It is unclear whether Mrs May will announce a direct replacement for Mr Green who was effectively her deputy prime minister.
Health Secretary Jeremy Hunt had been widely seen as the favourite for the post, although reports have suggested that she is reluctant to move him in the midst of an NHS winter crisis.