It came from nowhere, this the first real test of Ms May’s premiership: trying to find an explanation for why she had congratulated Jeremy Corbyn on the birth of a granddaughter that did not exist. She failed it spectacularly.

The Leader of the Opposition had begun Prime Minister’s Questions by congratulating his newly sacked chief whip Conor McGinn on the birth of his daughter, who had arrived in rather impromptu fashion and been delivered at home by the honourable member himself. This went on for some time.

That Ms May responded by congratulating Mr Corbyn, for reasons best known to herself, “On the birth of his granddaughter, I believe”, was telling for several reasons.

Personally, I stopped bothering long ago, but I had always assumed that the Prime Minister herself does still try to listen to what Jeremy Corbyn is saying at Prime Minister’s Questions. Clearly she struggles to tune in too.

That might be harsh. Perhaps she really does think that Jeremy Corbyn would begin Prime Minister’s Questions with a long and entirely irrelevant diversion into the birth of his own granddaughter. Stranger things have certainly happened.

It’s also possible she really does think that Conor McGinn, the member for St Helens North, widely understood to have orchestrated the wave of shadow Cabinet resignations that forced the summer leadership challenge, is Mr Corbyn’s own son. Again, stranger things...

Like Brexit and airport expansion in the South-east, the correct identification of inadvertently home-birthed children is a contentious issue, but it was still something of a surprise for collective Cabinet responsibility to be suspended yet again.

When the house erupted in laughter and the penny began its descent, the Prime Minister pointed to her right at party chairman and former chief whip Patrick McLoughlin, who had evidently given her the wrong intel, and said that “... perhaps one should never trust a former chief whip”.

Let us hope Ms May is not found out in next year’s Brexit negotiations, if only for the sake of whoever happens to be sitting next to her. Messrs Fox and Davis should begin practising their sudden powerslides under the table now.

Still, she’d recovered her composure by the end, in time to tell football’s world governing body, Fifa, that it was “outrageous” that they should seek to prevent the English and Scottish national football teams from wearing poppies in their match next weekend, and that they should “jolly well get their own house in order before telling us what to do”.