Theresa May has informed Parliament she is taking personal control of EU withdrawal negotiations, with new Brexit Secretary Dominic Raab "deputising" for her in talks.
Civil servants working on the negotiations will be brought together in the Cabinet Office Europe Unit headed by Olly Robbins - who reports direct to the Prime Minister - while Mr Raab's Department for Exiting the EU will focus on preparations for life after Brexit.
Labour said Mr Raab had been "sidelined" after just 15 days in the job, while the Best for Britain campaign described the move as a demotion reflecting the PM's "wafer-thin" confidence in her new minister.
But Mr Raab dismissed suggestions that his department had been downgraded as a "caricature", playing the changes down as "shifting of the Whitehall deckchairs".
He revealed that he agreed the changes on the day he was offered the job following David Davis's resignation earlier this month.
"The Prime Minister suggested it to me," Mr Raab told the House of Commons Exiting the EU Committee.
"On taking up the appointment, we had a very sensible conversation about the crossroads of the negotiations we are in, some of the tensions that were widely reported."
Mr Raab said he and the PM discussed "what we do to make sure we have the optimum arrangements - one team, one negotiation, clear chain of command - that would put us in the very best professional position to get the best deal".
The new minister let slip details of the new arrangements in the House of Commons last week, when he was asked if he would be "calling the shots" in his new job.
He replied then: "No, it is the Prime Minister and the Cabinet. I will be deputising for the Prime Minister in the negotiations."
Now Mrs May has spelt out exactly how the change will work in a written statement to MPs.
"DExEU will continue to lead on all of the Government's preparations for Brexit: domestic preparations in both a deal and a no-deal scenario, all of the necessary legislation, and preparations for the negotiations to implement the detail of the Future Framework," she said.
"I will lead the negotiations with the European Union, with the Secretary of State for Exiting the European Union deputising on my behalf.
"Both of us will be supported by the Cabinet Office Europe Unit and with this in mind the Europe Unit will have overall responsibility for the preparation and conduct of the negotiations, drawing upon support from DExEU and other departments as required.
"A number of staff will transfer from DExEU to the Cabinet Office to deliver that."