Bob Diamond is full of energy and enthusiasm. He likes taking risks. He is determined: he knows what he wants and goes for it. He is fearless, cheerfully taking on a job he has little experience of. He speaks (relatively) simply. He has been known to throw tantrums. He is greedy and always wants more. I’ve never met him, but on the strength of what I’ve been reading about him I’m absolutely confident that he’s going to make an excellent new chief at Barclays. This is because he accords perfectly with a brand new theory of leadership that is surprising, radical, yet utterly compelling. This theory says that the best CEOs are just like toddlers.