If we’re very lucky we’ll soon wake up to discover the past two years has been like the series finale of Dallas in which everything that had happened in previous episodes had merely been a bad dream. But until then we have to assume that the political leaders we have are real and treat them as such. Something that is getting harder by the day as they find new ways of redefining mediocrity. Each week the bar seems to get lower and still Theresa May and Jeremy Corbyn are unable to clear it.

With the government in chaos over both Windrush and the customs union, prime minister’s questions should have been a stroll in the park for the Labour leader. A chance to make May look weak with a series of well-aimed jabs before Thursday’s local elections in England. And initially it looked as if Corbyn had understood the brief as he got to the heart of the government’s difficulties by asking if the prime minister felt guilty that Amber Rudd had been forced to resign for her own failures.

Even though the question can’t have come as a surprise, May found herself unable to answer it. A look of confusion crossed her face as the two synapses of her brain tried to establish a connection.

No joy. Instead she glanced at her notes and started reading out a statement about how she was going to do the bare minimum to investigate what had gone wrong in the Home Office – if only she could remember who had been in charge for six years – and hoped that everybody would apologise to her when the inquiry, whose results she already had in her possession, found that she had done nothing wrong.

Corbyn didn’t appear to notice that his question had gone unanswered and retreated back to his script. Blah, blah, blah, the economy. And this set the pattern for the rest of the exchanges. Time and again the Labour leader would have the prime minister on the ropes – on Home Office deportation targets, on her own decision to deny visas for people wanting to fill the 100,000 vacancies in the NHS – and each time he would let the moment slip by meandering on to another topic. Blah, blah, the NHS. Blah, blah, blah, education. Blah, blah, blah, police cuts.

It eventually became clear that Corbyn had no real interest in asking the prime minister any questions. Not because he already knew she was incapable of answering them, but because he was really only concerned with collecting a series of video clips of him shouting about all the things he didn’t like about the Tories that he could post online to try and boost the Labour vote in the local elections. All of which suited May just fine as she was free to say whatever she liked without fear of being contradicted. The Maybot is as the Maybot does.

PMQs had seldom felt quite so pointless and the session quickly descended into near farce when it emerged that no one else had any questions for her either. Tory Eurosceptic Peter Bone forgot his disagreements with her over the EU, hailed Theresa as the Brexit queen and declared his intention of building a statue to her. A fitting monument to the patron saint of hopelessness.

There was a hint of tension when Amber Rudd rose to make her first intervention from the backbenches, but it soon became clear she was going to abide by her non-disclosure agreement. Though she looked demob happy – it must be a relief to no longer have to clean up after Theresa – she declared her undying devotion to the prime minister. May responded in kind, saying Amber should be very proud of having screwed up and implying that her failure would be rewarded with a return to the front bench before long.

Only a couple of SNP and Labour backbenchers came close to putting May on the spot. Inevitably, her algorithms went into a meltdown and she started barking staccato bursts of nonsense. The hostile environment wasn’t really hostile, it was just compliantly unfriendly. The customs union would be resolved by divine intervention. “We’ve been very clear,” she said to general derision. She hadn’t, of course. Then she never is. But on this occasion it hadn’t really mattered.