It was as naked a moment of hostility as could be imagined, given their constitutional roles. For years John Bercow has irritated the prime minister, but today David Cameron's sense of entitlement overcame him in an extraordinary Commons outburst.
Cameron was just finishing his final answer to Ed Miliband, rousing himself to a testosterone-filled flourish, when Bercow interjected, presumably over the noise in the Chamber. We never found out, because before he could stop himself Cameron let slip the words: "Well I hadn't finished."
The Commons chamber exploded. The tone was unmistakably irritable and resentful. Tory MPs loved it. Finally the prime minister was making his anger at the Speaker plain.
I got the sense that Cameron really didn't mean to say it. He looked instantly bashful once he realised what had come out his mouth. The Commons cheered and he laughed along nervously.
The outburst was more revealing for how instinctive it was. Cameron was never the most humble of men and the social trappings of power have evidently made him unaccustomed to being interrupted.
The noise continued for some time. It had been a dire PMQs and MPs evidently welcomed a moment of real drama.
Bercow had no option but to make a point. If the Speaker doesn't rule the chamber he has no function. So once the noise died down, he told the prime minister coldly: "He can take it from me that he has."
This was how men who genuinely detest each other actually speak. It contrasted sharply with the rehearsed pantomime which preceded it from the leader of the opposition.
Miliband had a fairly good line on the Royal Mail sell off and the role of these 'preferred investors' who cashed-out with millions. The Labour leader dealt with specifics which never got an answer. Cameron dealt in generalities which were never intended to deliver any.
Tory MPs are not complex creatures, they will cheer anything as long as it features the phrases "privatisation" or "sold off our gold" or "Michael Foot". Cameron used this predictability to good effect, regularly rubbing his backbenchers' tummies for some vocal support.
It would have been easy to feel sorry for Miliband, except that his final question was such a cut-and-paste job ("cost of living crisis", "stands up for the wrong people") that any positive sentiment was lost. It was a relief when Cameron could turn his attention to the man he really hates.
Snap verdict: Miliband: 2 Cameron: 1