Gordon Brown's comment about Gillian Duffy, calling her a bigot is a career-limiting comment on a monumental scale.
The man must have visualised the removal vans driving away from Number 10 Downing Street, with his family's belongings in it, as he heard his comments played back to him.
It's one slip, which was inadvertently recorded by the media, but that's enough to bring you down. Ask tarnished jewellery retailer Gerald Ratner.
If this had been an isolated incident, Brown's tenure as leader of the Labour party would still be in doubt, but it comes after other stories of a hair-trigger temper. Having control over one's feelings is a core leadership characteristic that he lacks to a worrying degree. His position now must surely be in question, even if -- miracle of miracles -- Labour manages to persuade the electorate it is still the party of government.
We all make injudicious comments, but being as experienced with the media as Brown is, he should have remembered he had a microphone on his lapel.
Now that Brown is trying to repair the damage, what's his strategy? First, he's come out with an apology, which is definitely the decent thing to do, but Brown has been saying sorry quite a lot recently and what was once a bold diffentiator, casting his rivals with less integrity, is now just highlighting a catalogue of mistakes.
Second, he's playing the blame game by rounding on his publicity advisors for putting him in front of Duffy in the first place. It's a common reaction from business leaders according to blogger Nick Taylor, which springs from being too used to command and control style.
Letting it be known that any challenges to your way of thinking will not be tolerated, by blaming the people that set it up, will only ensure that people only tell you what you want to hear, not what they really think.
Yesterday's gaffe by Brown demonstrates how he is lacking in some key leadership skills. Taylor sizes him up well by saying: "He is what he is. He is one of the greatest chancellors there ever was, he knows the numbers, he would make a great FD, he is a policy guru but he is not a natural leader and even less a communicator."