I think David Aaronovitch is pretty close to the truth with his analysis of Ed Miliband's character

And in this moment of crisis it became clear — as it does — what Mr Miliband is. A personable man (and he is a very pleasant companion), politically he is not a presence at all, he is an absence. He is Oedipal Ed, the negator of the unpopular actions of the fathers; the anti-Blair, the non-Brown. His technique for victory to is follow behind the leader, wait for a slip-up and exploit his or her mistakes. He did it to his brother. He hopes to do it to David Cameron. He is neither hunter nor prey, he is scavenger. He is a political vulture. Mission creep? His mission is all about creeping.

David Aaronovitch, On Ed Miliband in the Times (£) on 5 Sep 2013