No one can say that Theresa May doesn't go out of her way to make things easy for Jeremy Corbyn. There was a time in their early exchanges at prime minister's questions when the Labour leader frequently failed to follow his own line of thinking and managed to confuse himself as well as his opposite number. But after some coaching from May, whose inner hopelessness one cannot help but admire, Corbyn has learned he really only has to repeat the same one-line question over and over again. Brexit, Brexit, Brexit.

Neither May nor Corbyn looked exactly rested for their first PMQs of the new parliamentary session – the summer months haven't been kind to either of them – but the Labour leader is rather more convincing when operating on autopilot than the prime minister. He forced an eye open, asked which of her ministers she agreed with over Brexit, and sat down.

The prime minister looked panic-stricken and immediately went into damage limitation mode. She actually agreed with all of her cabinet, even though they were all saying completely different things. Call it collective irresponsibility. She was aiming to get a good deal, but things wouldn't be so terrible if she got a bad one.

Think of it this way: back in 1918, 100 million people had died of Spanish flu and it hadn't been the end of the world. And she wasn't anticipating a death toll on anything like this scale: 20 million at the very most. What's more, a no-deal Brexit offered a whole range of exciting job opportunities. Undertakers, black marketeers, Portaloo operators on the M20. Even Bernard Matthews was enthusiastic about a no-deal. Great. Now the turkeys were voting for Brexit.

While there was some irony in Corbyn lecturing May on not having a clue about what she was doing on Brexit – the Labour leader has hardly been a model of clarity – the prime minister still struggled to come up with a credible response. She tried muttering “antisemitism” a few times as a diversionary tactic, but mostly she switched to her default monotone algorithm of wanting a deep and special partnership. Finding one with herself would be a start. Her backbenchers looked miserable. When she switches to Maybot, it's invariably game over.

As if anticipating her own mediocrity, May had arranged to give a statement on the Salisbury poisonings immediately after PMQs. The prime minister almost always does well on these occasions – she can do a nice line in sounding like a serious leader on most things other than Brexit and the Conservative party – and she was helped this time by having something interesting to say. Which seemed to come as much of a surprise to her as to everyone else.

Usually these occasions are much ado about nothing but it turned out that the police weren't quite as useless as she had suspected. They had identified the killers as two Russian agents from the GRU who had sprayed novichok around an east London hotel – the kiss of death for that establishment – before finding a train service that hadn't been cancelled to take them down to Wiltshire to poison the Skripals.

May went on to praise the European Union for standing up to the Russians – she didn't pause to wonder why we were so hellbent on leaving an institution that was so supportive – before announcing that although there was no point applying for an extradition order, she had issued a European arrest warrant for the two suspects. In hindsight, this might have been a mistake. After Brexit, it could turn out that the UK is the one place in Europe where the Russians can't be arrested.

The Labour benches had made a point of emptying before the prime minister had begun her statement. A silent protest against their own leader, whom they reckon to be a liability on security matters. Under the circumstances, Corbyn acquitted himself quite well. He was never going to go the full “I hate all the Russkies, they're a load of crazy commies”, which was all that would have satisfied many of his own MPs, but he did admit that the evidence was compelling and that the actions of the Russians should be condemned.

“Typical weaselly words,” bellowed Boris Johnson, showing no signs of having listened to the Labour leader and choosing instead to give the speech he had prepared earlier. It takes a weasel to know a weasel.