"With reference to Big Brother 2005, does Derek's belief that there is a mole in the house make him more or less suitable as leader of the Conservative Party? Is the level of paranoia a desirable trait for a politician? Show your working."
Remember, he could be out of the house, someone could apply for the Chiltern Hundreds, there could be a by-election, and he could be partly leader by the end of the year, assuming the good burghers of the town selected don't switch to the Lib Dems or whoever.