Like a lot of things, Prime Minister’s Questions doesn’t much matter, except when it does. Boris Johnson will have known that he was going to face some awkward questions about Matt Hancock, having been the last person in Britain arguing he should keep his job. But he had a stack of answers in his folder, or rather a stack of one answer, which was “vaccines”.

Keir Starmer opened by asking why the health secretary had been allowed to resign, rather than be sacked. Johnson replied that he had seen the Hancock story on Friday morning, and “we had a new health secretary in place by Saturday”.

Was the prime minister under the impression that he’d had something to do with this? It really sounded like he was. Perhaps he believes that, in a way, he did sack Hancock. He’s in charge, after all, and Hancock has gone. Must have been him, even if he’s not sure exactly what it is that he did to make it happen. Maybe, like the pharaohs of old, he also makes the sun rise. The Sketch imagines the Cabinet Secretary, Simon Case, greeting him each morning: “Daylight again! Great job, prime minister. Perhaps you should put your feet up for an hour or so after that effort.”

But Johnson wasn’t finished with the self-congratulation on this job well done. “Given that we have a pandemic,” he continued, “to move from one health secretary to the next with that speed was fast.”

Was it? The Sketch has covered a lot of ministerial resignations and reshuffles over the years, and the time between the resignation of Hancock and the appointment of Sajid Javid was pretty standard. It’s not clear why the pandemic would have slowed it down. Is the prime minister under the impression that Secretaries of State have to be shipped in from China? It would certainly be in the Cabinet’s interest to encourage in Johnson the belief that there was a global shortage of ministers. It is indeed the best explanation of why some of them are still in post.

To Starmer, this was “ridiculous”. Had Johnson sacked Hancock or not?

The prime minister’s reply was quite good. Starmer, he said, “spent three days trying and failing to sack his deputy leader, whom he then promoted.” The Tory benches loved it, and Angela Rayner, the Labour deputy in question, was laughing too. Starmer had no choice but to take it on the chin, and point out that Johnson was still taking credit for events in which he seems to have been at best tangentially involved: “In a minute, he will be telling us that he scored the winner last night.” Johnson offered a modest nod of the head at this point. Maybe he thinks he did.

Starmer wanted to know how Hancock had been able to hire his lover as non-executive director of the Department of Health. Johnson replied that she, too, was no longer in the job, although again it is unclear this was his doing.

The Labour leader was halfway through his questions now, and the prime minister was looking relaxed. Every time he was asked about the Department of Health, he could simply reply “vaccine rollout”. He may have felt he was going to be able to drag things out to a no-score draw.

It was a horribly misjudged answer to a question about a mother’s grief at her son’s lonely death

And then Starmer sprung a trap. Ordinary people had made sacrifices to follow the rules, he pointed out. “Take the case of Ollie Bibby,” he said. There was chuntering from the Tory benches. “I’m sorry,” the Labour leader told the prime minister, “you might want to listen.” They went quiet at that. The 27-year-old, Starmer explained, had died of leukaemia the day before Hancock was captured on camera. In the weeks before his death, only one family member had been allowed to see him. His mother was appalled that the health secretary had broken rules that had caused her family so much pain. How, Starmer asked again, could the prime minister have believed on Friday that Hancock should stay in his post?

Johnson tried to shift gear. “We all share the grief and pain of Ollie had his family,” he began. But he’s never been keen on touchy-feely moments (except in the Hancock sense, obviously) and so he swiftly switched to anger, jabbing his finger at Labour. They, he explained, were “focusing on stuff going on within the Westminster bubble,” whereas he was focusing on, you guessed it, vaccines. He offered some statistics about how well they were going. It was a horribly misjudged answer to a question about a mother’s grief at her son’s lonely death, and the anxiety that flashed across his face suggested that he realised this even as he said it.

Starmer offered quiet outrage. Ollie, he said, was not part of the Westminster bubble. His family had followed the rules. Johnson stared at the folder in his lap. The MPs behind him were silent.

“There is a pattern here,” Starmer said, running through Dominic Cummings, Robert Jenrick, Priti Patel and, of course, Hancock. “Every time it is the same old story. While the British people are doing everything asked of them, it is one rule for them and another rule for everybody else.”

Johnson retreated to bluster. “The whole country,” he said, could see how quickly he had appointed Javid. It really did feel as though he wanted some sort of prize for having accepted Hancock’s resignation.

PMQs doesn’t win any elections, but every now and then it does reveal something. Sometimes, the prime minister’s habit of describing the world as he would like it to be can leave opponents confounded.

But on Wednesday it left him looking disconnected and aloof. Labour has found an attack line that it can keep using. The struggle that Johnson will have with “one rule for you, another one for me” is that it’s the motto by which he’s lived his whole life.