The new Conservative leader will be announced on Tuesday 23 July, the party says – but the date when he will become prime minister is still being kept under wraps.
Voting in the leadership contest will end at 5pm on the day before, with the winner unveiled after overnight counting.
However, a brief statement failed to shed light on whether Theresa May would remain in No 10 for a swansong prime minister’s question time the following day, before resigning.
Some MPs have protested such an arrangement could allow her successor to escape scrutiny until the autumn – because their long summer recess begins one day later, on Thursday 25 July.
Aides to Boris Johnson and Jeremy Hunt were told the winner of the leadership race will not move into No 10 immediately on 23 July, as widely expected.
There is a precedent from 2007, when Gordon Brown was declared the new Labour leader three days before becoming prime minister, so Tony Blair could enjoy a valedictory last Commons appearance.