@Stuart White: The
Cabinet Office rule - book (draft of chapter 6, approved by the House of Commons Select
Committee on Justice and drawn up in consultation, I
understand, with the party leaders and with constitutional experts) lays it down that after an election the incumbent prime minister has a duty, as well as a right, to remain in office until there's clear and incontrovertible evidence that someone else is definitely in a position to command majority support in the house of commons.
I
understand that this letter reflects Cameron's frustration that in the past, decisions have been taken by the relevant
Cabinet committee and then disappeared into a bureaucratic fog.