TTT,
// Hang on Gromit, can you clarify, even if Cameron is still PM after the election you think that the party will dump a leader in office? //
I have explained it once. This article on the YouGov website explains the problems for Cameron if he fails to win a majority this time, which is the probable outcome. If There are enough UKIP seats and LibDem seats to vote for Cameton's minority Queens speech, then he is ok, in the short term. If he cannot get enough to Support his minority Government then the prospects look bleak for Cameron. Here is what YouGov say...
// David Cameron will be Prime Minister on 8th May. And probably 9th May. Indeed, he will step down only if and when he decides he can’t win a majority in the House of Commons for a Conservative Queen’s Speech. In that case he will resign as PM and advise the Queen to ask Ed Miliband to form a government.
The Tories, having acknowledged defeat would themselves face either a leadership election (if Cameron resigns as party leader as well as PM) or a leadership crisis. //
https://yougov.co.uk/news/2015/04/29/why-its-so-hard-cameron-win/