I was reminded of one of David Cameron’s last Prime Minister's Questions this week. He had already lost the referendum and announced he would be resigning, so he could say what he thought. He addressed Jeremy Corbyn directly: “For heaven's sake man, go!”

That was not his usual line, which was to welcome Corbyn’s survival as leader of the opposition as the best thing possible for the Conservative Party. Indeed, Tory MPs generally used to cheer ironically when Corbyn stood to ask his first question. Oddly enough, they didn’t even bother to do that today. Theresa May made the usual weak joke of saying how pleased she was to see him in his place, but it wasn’t funny.

Cameron’s point was, I think, that a weak opposition was bad for the Government, and a weak leader of the opposition was bad for the Prime Minister. Today’s session illustrated that well.

Corbyn asked five questions about housing, which is an important subject. But his questions were so poorly framed that it wasn’t clear what the Goverment was doing wrong and what it should be doing instead. So May resorted to answering questions she hadn’t been asked, along the lines of, “Isn’t the private rented sector terrible?” and using them as the prompt for a little homily about Conservative values: “He wants to see the government owning everything, the government doing everything for everyone...”

Apart from that, her answers were stumbling and forgettable and her one prepared joke – something about Corbyn sitting on the floor of a train: “Even on rolling stock he's a laughing stock” – was worse than anything Corbyn has ever inflicted on the Chamber.

You need a good opposition to bring out the best in government. Which was why it was even more inexplicable that Corbyn chose to change the subject for his sixth and final question. He decided to ask a question about the effect of benefit changes on women’s refuges. His only motive can have been to avoid asking anything that his rival Owen Smith had suggested asking in a mischievous news release this morning.

Theresa May questioned on single market

Because, as May was able to point out obliquely in her answer, protecting women from domestic violence is one of the subjects on which she is well-informed and in which she had something of a track record at the Home Office. She said how important the question was and promised to review the benefits change.

It was Angus Robertson for the Scottish National Party who showed how PMQs should be done. He asked a question that May didn’t want to answer: did she want Britain to stay in the EU single market after Brexit? Suddenly there was tension in the House as May was forced to account for herself.

She didn’t answer, because she doesn’t want to close off options in her negotiations, so she accused the SNP, in effect, of not “respecting the views of the British people”. Robertson responded that his MPs “respect the views of the people of Scotland”.

For a moment, May was tested.