Civil servants at Priti Patel's Department for International Development have been told to expect a new minister, The Independent understands.
Staff are already preparing to welcome a new secretary of state, with Ms Patel expected to be sacked in the next few hours.
The cabinet minister is set to lose her job after holding a series of meetings with top Israeli politicians - including the country's Prime Minister Benjamin Netanyahu - without informing Downing Street.
Speculation about Ms Patel's future in the cabinet has been mounting as she headed back to the UK from Africa, having cut her visit short amid the growing storm surrounding her meetings.
But insiders at DfID have told The Independent they have already been informed that a change at the top of the Whitehall department is coming.
Names in the frame as a potential replacement for Ms Patel's cabinet post include Rory Stewart and Alistair Burt, both of whose current jobs straddle DfID and the Foreign Office, and junior defence minister Tobias Ellwood.
Ms Patel's political ambitions appear to have unfolded in just five days after it emerged last week that she held a number of meetings while on holiday in Israel at which official departmental business was discussed.
Despite one of the meetings being with the Israeli Prime Minister Benjamin Netanyahu, Theresa May was not informed of them in advance.
At a meeting with Ms May on Monday, Ms Patel was censured for breaking protocol, apologised and had seemed to have avoided more severe consequences.
But it emerged on Tuesday that some details of what was discussed at the meetings she had while on holiday in Israel and at least one further meeting with an Israeli politician that took place after her holiday, had not been divulged to Ms May.
In particular, Number 10 was not told about a meeting Ms Patel had with Israeli public security minister Gilad Erdan in Westminster on 7 September.
Downing Street is said to have lost patience with the International Development Secretary, after the extra details emerged and Ms May's actions also started being pulled into the row.
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