It’s not always a great look for a prime minister to have to publicly restate his confidence in his home secretary just a matter of days after reappointing her to the job. A bit like a football club chairman offering his full support to the manager just days before sacking him. But for once in his life Boris Johnson has been entirely genuine. Hard to believe, I know, from someone for whom dishonesty is a way of life, but true nonetheless.

Boris really, really does value Priti Patel. He doesn’t care if she bullies her staff a bit. He cares even less if intelligence officials don’t entirely trust her on matters of national security. Because that’s not the point of her. Just as the home secretary can never be too Brexity or dog-whistle rightwing, she can also never be too stupid or incompetent. These are the qualities Boris most admires, having gone to some trouble to eliminate every cabinet minister who showed the slightest sign of having any independence of thought. Or even of having a mind at all. Priti Patel’s sole purpose in government is to be Priti Vacant.

In her statement to the Commons on her new points-based immigration system, Patel was at pains to live down to expectations. If there were a points-based tally for a home secretary, then it’s a racing certainty Priti would never have got the job. After all, this is the woman who responded to a terrorist incident by declaring war on counter-terrorism. On three occasions. She has turned her lack of ability into a piece of performance art.

What she does have, though, is the effortless self-confidence of someone who doesn’t have a clue just how dim she is. She makes no effort to disguise her ignorance. Rather, she revels in it. And as she ran through the proposals the government had announced during recess the previous week, her smirk and swagger became steadily more pronounced. The country was wanting this, the country was loving this and the country was getting it.

For reasons that weren’t entirely clear, Diane Abbott chose to sit this one out on the Labour frontbench and let her junior shadow home office minister, Bell Ribeiro-Addy, point out some of the new systems’ more obvious flaws. That it failed to distinguish between low-paid and low-skilled work. That it would leave huge staff shortages in many sectors. That it presumed the reason most Brits weren’t already doing these jobs was because immigrants had stolen them off them. Rather than that they just didn’t fancy doing them.

Patel sighed ostentatiously and insisted that Ribeiro-Addy was just too stupid to have understood the proposals properly. Pots and kettles. At which point, Jeremy Corbyn intervened to say things might work a little better if the home secretary was a little less condescending. Priti merely replied that she too required courtesy and patience. Again, pots and kettles. The irony meter was now off the scale. Not even her friends have known her to be patient and courteous.

Most ministers might have a sneaking suspicion they are heading off the rails, when the first four Conservative MPs to stand up to praise their intelligence and attention to detail are the notorious screw-balls Iain Duncan Smith, David Davis, Owen Paterson and John Redwood. But Priti was in her element. Her coup de grace was her insistence that the British people had voted for massive staff shortages in the NHS and social care. And if people were determined to die or grow old in squalor then she was proud to be delivering on the will of the people. Back in No 10, Boris could only applaud. This was the Priti he knew and loved so much.

Exit one brainless cabinet minister. Enter another. The environment secretary, George Eustice – Useless Eustice to his admirers – was at the despatch box to explain why the government had done so little about the floods. Eustice’s main observations were that it had rained much more than expected and that really most people had no one to blame but themselves for buying homes that had been built on vulnerable flood plains.

Labour’s Luke Pollard expressed his pity for Eustice – it wasn’t his fault that he wasn’t very good at his job – and wondered instead why the prime minister had gone missing in action and had chosen to put his feet up at the nation’s expense in the grace-and-favour mansion in Kent. Useless was outraged on his master’s behalf. Boris had never pretended to be anything other than a bit lazy and it was going to take a great deal more than a few damps patches to get him out of bed.

“Look,” said Eustice, trying to convince himself as much as everyone else. Boris had been to visit some flood victims in November and if he were to make another visit it would only encourage more people to flood their homes. Besides, the prime minister wasn’t the sort of showman who thrived on attention and media opportunities: he was the master of dialectics. The details man who got things done precisely by failing to grasp the details. Not waving but drowning.