The fact he won't admit about being pm is completely obvious. It is clear he doesn't want to get involved with that whilst Cameron is still the leader and in office. It would undermine his party and weaken their position at the next election
No politician in his position would admit to that. He will admit it when the time is right because shock horror he wants to win so will announce it when it is the best time to and not before. Being straight talking does not mean giving your opinion in everything so transparebtly at all times, if he were to do that then he would be committing political suicide but he is a darn sight better than every other politician I have had the misfortune to listen to. But then you know all this...