Blair was not prepared for Short's attack
Tony Blair will have been braced for a characteristically blunt assault from Clare Short.
But few would have predicted just how brutal, personal and potentially damaging her attack would be.
And probably not even the prime minister would have expected her to go on to demand his resignation to allow an "elegant succession."
Leaving aside the fact that such an event is a contradiction in terms, everyone knows what she means. She wants him to step aside for Gordon Brown.
But in taking that extra step, she may well have undermined what was otherwise an astonishingly powerful speech.
She accused the prime minister of being so obsessed with his own place in history that he was turning into a dictator.
He was in danger of destroying everything he has already achieved and undermining the very foundations of the Labour government, she said.
She broadened her attack beyond Iraq to take in the public services and the whole style of government which, she said, had become centralised and dictatorial.
And she suggested Mr Blair's presidential approach was stretching party loyalty to breaking point.
The prime minister will want to brush it aside, and Ms Short's previous behaviour will help him do that. Her demand for his head actually makes that easier.
Apart from the usual suspects, who have been there since before 1997, there ares still few on the Labour benches who want to risk losing their main electoral asset.
His personal popularity amongst voters would have to fall further before that became a real plot.
It was also notable that, unlike Robin Cook, she did not receive an ovation from her colleagues when she ended her speech.
There is always a point in a powerful leader's reign when they start the downward slide
Many on the Labour benches remain deeply annoyed by the way Ms Short has behaved over the past few months and they are not ready to rehabilitate her just yet, if at all.
Her speech will certainly have helped her standing with some of her colleagues. But she is nothing like the political force she could have been.
The most damaging thing about her speech was the comprehensive nature of the criticisms.
Unlike Mr Cook, she did resort to a personal attack on the prime minister - who previously let it be known his morning conversation with her had been perfectly affable.
And in one relatively short speech she summed up much of the criticisms regularly levelled at the prime minister and New Labour.
Her comments may do little for her standing in the Commons, but the danger for the prime minister is that they may well feed into a more general public perception.
Ms Short has always been seen by voters as one of the most honest and straightforward politicians in Westminster.
She may have blown some of that with her recent behaviour. But she is still one of the few ministers the public recognises and has time for.
There is always a point in a powerful leader's reign when they start the downward slide.
With Margaret Thatcher, for example, it was a couple of years before her demise and when she too was seen as out of touch and dictatorial, particularly over the poll tax.
Former minister Geoffrey Howe was then on hand to deliver the killer blow with a devastating assault in a resignation speech to the Commons.
No one would claim Ms Short is in anything like that league. Even Robin Cook's resignation speech was not comparable.
But much more of this and it will not be inconceivable that, in the future and in retrospect, the events surrounding Iraq might be seen as having sown the seeds of Tony Blair's demise.