Being assertive and sounding confident is always a good start. No leader of the opposition is going to get far without those qualities. And Kemi Badenoch certainly manages that. But winning at prime minister’s questions requires something more basic than that. Something fundamental. A very basic understanding of the facts.

Not just reading a headline in the papers and a few posts on social media. Not just listening to a junior minister sound a bit confused on the Today programme. You need to put in the hard yards. Or at least do some very elementary research. Otherwise you risk coming badly unstuck.

And on Wednesday, Kemi did just that. Exposing herself as lazy and shallow. So much so, that she didn’t even realise she had just made a fool of herself. But then, neither did any of her MPs. For reasons that aren’t entirely clear, Kemi remains the party darling. The most popular member of the shadow cabinet by a long way.

There again, most of the rest of her team are deadbeats. So maybe she really is the best the Tories have to offer. Maybe they like a leader who responds to the loss of more than 500 councillors by insisting the Tories have suffered no losses. The councillors have just been mislaid. Lost down the back of the sofa.

For Kemi, all preparation is time wasted. Time that could have been better spent picking a fight with someone. So she started with the absurd line that Labour not increasing fuel duty in the autumn was another U-turn. One that had been achieved only through her campaigning.

The reality was that the fuel duty increase was never going to be implemented. Just as it hasn’t been for the past 15 years. And the 5p cut has been maintained since 2022. The Tory leader thought she had delivered a killer line. The reality was that she had just made herself look a bit stupid, trying to con the public that they hadn’t really understood the situation.

But that was only the start. If all Kemi had done was to try to claim the credit for something she hadn’t done, then this could have been a half-decent PMQs for her. At the very least, one that was totally forgettable, where neither she nor Keir Starmer did more than trade words of little importance. Instead, she chose to double down on her ignorance, and let everyone know she really did have only the most slender grasp on the realities of global politics.

Even worse for her: she did it with such certainty. With such aggression. As if she truly believed she had Starmer bang to rights. How was it that the government had relaxed its sanctions on Russian oil? Why were we now allowing oil into the country that had been previously prohibited? This was a betrayal of everything the government had said it stood for. Soon Starmer would be taking down the flag of Ukraine and raising the Russian one.

If this had been true, Kemi would have had a point. The hypocrisy of securing Russian jet fuel so we can all have a summer holiday abroad while publicly claiming the moral high ground would have been overpowering. But it wasn’t. It was just plain wrong.

It wasn’t entirely clear what Starmer had been expecting to come his way at PMQs. It just wasn’t this. He has had a bruising 10 days or so, and must know deep down that the game is up. That he can’t carry on as prime minister for much longer. There were a few signs that reality was breaking through his denial. It was there in the tiredness in his eyes. In the touches of self-deprecation (something you almost never see in him). In the attempt at a jokelet involving Andy Burnham and Pep Guardiola. The laughter was mostly sympathetic. Some MPs appreciate a trier.

Still, Keir wasn’t about to look a gift horse in the mouth. Let me explain, he said. In words of one syllable. The sanctions were not being reduced, they were being increased. There were now more sanctions than there were yesterday. Previously – as under the Tories – Russian oil that was processed in third countries had been freely available in the UK. This was now going to be phased out gradually. So some of the oil would continue to be part of the supply chain for a limited period of time.

At this point, some of us began to wonder if Labour hadn’t deliberately planted the idea that it was reducing sanctions, just to confuse Badenoch and other Tory MPs. And, as it happened, some of their own MPs. But then we gave our heads a wobble. This is a Downing Street where most of the occupants are busy refreshing their LinkedIn pages. They simply aren’t capable of something so subtle. So it was just a common or garden communications screw-up.

Kemi, though, was unable to accept the evidence of her own ears. She still believed Labour was lifting sanctions – and if she believed it, then it must be so. Because she was capable of bending reality to her will. Time and again she repeated her assertion that what she had said was the truth. And time and again, Starmer tried to explain what had happened. Even going so far as to say the Tories had done the same thing when they had been in power.

“Don’t be so pompous and patronising,” Kemi said, in her most patronising tone. Keir shrugged. What else was he supposed to be when the leader of the opposition was so wilfully half witted? He couldn’t really help himself. And with that, their exchanges rather petered out. A strange encounter between a prime minister who was out of time and a leader of the opposition who was out of touch.

Later that afternoon, Wes Streeting – flanked by about 25 of his friends – appeared on the backbenches to deliver his resignation speech. If you can call it that. It wasn’t a patch on his resignation letter. The criticism of Keir was heavily coded: if you blinked, you missed it. Most damning of all, it was just a little dull. This was about ambition, not principle. A leadership campaign speech in which he made no attempt to say what he would do differently. You half wondered if Wes was feeling he had been a little hasty in giving up his cabinet post. Robin Cook or Geoffrey Howe this wasn’t.