Who runs the country when Cameron is on holiday?
Nick Clegg is the Deputy Prime Minister.
This morning, Mr Morus informs us that William Hague has taken Lord Mandelson's previous title of 'First Secretary of State'.
For these two titles not to reside with the same person begs the question of who is in charge when David Cameron is on holiday or otherwise indisposed.
There is no doubt that Liberal Democrats will expect their man to be left in sole charge at Number 10: he is, after all, the Deputy Prime Minister. That is, he deputises for the Prime Minister when the Prime Minister is unable to fulfil his duties.
But Conservatives would find this more than a little unpalatable. It would not only provoke even greater fury on the back benches (as if they were not already seething enough). But Conservatives and non-Conservatives the length and breadth of the nation might just wonder how the leader of the party which came third in the General Election ends up running the show.
Yes, we know this is a coalition. And we perfectly understand that a few manifesto pledges had to be traded away in order to arrive at a working partnership.
But the Liberal Democrats are not equal partners in this coalition, though they appear to be behaving as though they are and David Cameron uses an awful lot of flattering rhetoric to maintain that impression.
It even transpires that Mr Hague and Mr Clegg are 'time-sharing' the 3,500-acre Chevening House in Kent: it is to be their official country residence on alternate weekends.
Yet this is traditionally the grace-and-favour home of the Foreign Secretary alone.
It ought to be evident to any fair-minded person that, when David Cameron is away, William Hague ought to be left in charge.
How else can we be sure that a Conservative programme of government (if it be) is sustained?