Highlighting your own party's divisions over policy is not a good tactic at PMQs, Jeremy Corbyn

The Labour leader suffered one of his worst ever weeks to an almost deserted chamber. Soon PMQs will just be Theresa May and Jeremy Corbyn jabbering at one another in an empty room

Jeremy Corbyn attacked Theresa May over tax cuts his own chancellor supports (Parliament Live)

Every week fewer and fewer MPs bother to turn up to Prime Minister’s Questions. Wednesday’s edition was the most sparsely attended I can recall.

Both the back benches were half empty. No one stood at the bar of the house. At this rate of attrition, it may soon just be Theresa May and Jeremy Corbyn jabbering at one another over the despatch box. If it was a theatre – and it is meant to be theatrical – we would be nearing the point at which the show was shut down.

On the infinitesimally small chance you care, I can report that Corbyn had one of his worst weeks, and there is no shortage of them to choose from, while May had one of her best. Bizarrely, the worse things get, the more serene she seems to be.

Seven cabinet resignations in a year, and from very high profile jobs, would lessen some prime ministers. But now May has replaced them all with non-threatening non-entities, she seems far more content. She is a micro manager, and Boris Johnson and David Davis were not easily micro-managed. These days, most of her senior ministers are indistinguishable from inanimate objects, which is just the way she likes it.

In the Budget on Monday, Philip Hammond re-announced the end of austerity. I said at the time that it may prove to be one of the most stupid bits of political strategy in decades. Being told austerity is over when, in your life, it is palpably obvious that it isn’t will drive voters to Corbyn, who absolutely no one doubts would end austerity as fast as he possibly could.

But I hadn’t considered the man’s overwhelming lack of any kind of political nous. One measure in the Budget was to raise the starting point for the higher rate of tax, benefiting anyone who earns more than £46,000. On Tuesday, John McDonnell said he would not reverse this increase, and leapt to the defence of those who would benefit from it.

“We are not going to take funding away from people,” he said. “Some of these are middle earners, we’re talking about head teachers and people like that who have had a rough time as well as everyone else.”

He said this because he is positioning Labour for a general election he is agitating for, and seeking to widen the pool of people that might consider voting Labour – which is what politicians do because it is what politics is.

And yet here was Corbyn attacking the very tax cuts his shadow chancellor had been defending.

That’s his right. According to independent analysis, half of the benefit from raising the income tax threshold will go to the top 10 per cent of households. If Jeremy Corbyn wants to badge this as “tax cuts for the rich” then he can. But to attack the prime minister over something your own shadow chancellor agreed with only the day before, and defending head teachers as he did so, is something only Jeremy Corbyn can do.

As he prattled on, the Tory benches howled at him. They wanted to know the answer to a straightforward question. If you earn, say, £50,000, then from April next year there will be something like £40 a month more in your take home pay. McDonnell thinks this is a good thing. Corbyn thinks this is a bad thing. So if you’re thinking about voting Labour, but not sure if you’re going to get that money taken away again, I’m afraid I can’t help you. And nor can they.