Can it be that Jeremy Corbyn has done Theresa May a good turn? For by revealing the existence of many millions of voters who imagine the Government can just spend, spend, spend, he has forced the Prime Minister to start delivering lessons in Economics for Beginners.

Margaret Thatcher never tired of giving such tutorials. She was so keen on telling people the economic facts of life, she would lecture on the subject even to colleagues who might have been thought in no need of instruction.

Corbyn invited the Prime Minister to confirm, “after a week of flip-flopping and floundering”, whether the pay cap for public servants will remain in place until 2020.

He added that “the prime minister found one billion pounds to keep her own job”, after which he dilated on “hard-working nurses” who “have to access food banks to survive”, insisted that the prime minister “simply doesn’t get it”, and said low paid workers “deserve to be given more optimism rather than greater inequality”.

The Leader of the Opposition sounds better than he did. The general election has conferred on him a kind of legitimacy. He has shown that he speaks for a lot of people.

But May was not going to give him, or them, anything so facile as more optimism. She instead decided to dole out some realism. What happens when you don’t deal with your deficit?

Could she be about to threaten us with Venezuelan conditions? Was she going to go Caracas?

No, they must have decided in Number Ten that a European example would carry greater weight. So she warned that if we don’t deal with the deficit, we can expect a future like Greece, with “spending on the health service cut by 36 per cent – that doesn’t help nurses or patients”.

How refreshing to get some straight talking on the need for Prudence, the austere and virtuous lady to whom Gordon Brown used to proclaim his admittedly rather self-interested attachment (“Prudence with a purpose,” as he called her in his 1998 Budget), only to jilt the poor maiden and set off the unsustainable boom from which we are still struggling to recover.

So we are indebted to Corbyn for forcing May to talk about economics. Long may she continue to do so, with Philip Hammond nodding sagely at her side. How reliable she sounds as she does it.

If she has put her gambling days behind her, the nation might eventually decide it prefers sticking with her to taking a punt on Corbyn the optimist.