Here in the UK, we used to say, “Remember, remember the 5th of November,” referring to the day Guy Fawkes tried to blow up the Houses of Parliament. More than 400 years later, his effigy still gets ceremonially burned on bonfires across the country.

These days, however, the national chant seems to have become, “Remember, remember the last Autumn Budget.” Every year the nation waits nervously for what might emerge from the Chancellor. Tax rises, spending cuts, new rules, old rules, borrowed money, unborrowed money. Entire newspaper supplements are produced to explain events which have not yet happened.

Last year was particularly memorable. The anticipation was so intense that it almost risked creating the recession everyone was worried about in the first place. As someone once said, we have nothing to fear but fear itself. Although they probably never had to sit through eight weeks of pre-Budget media angst!

A great deal of that anxiety stemmed from changes in forecasts for productivity. Rachel Reeves’ famed ‘fiscal headroom’ disappeared as the economists at the Office for Budget Responsibility (OBR) cut their expectations for UK productivity growth. And these aren’t small numbers. Even relatively modest changes in productivity assumptions can move the public finances by tens of billions of pounds. Entire Budgets are constructed around numbers far smaller than that. More tax rises followed.

So why is productivity so important?

Well, productivity is the economy’s magic trick. It is the almost invisible force that allows living standards to rise without everybody working longer hours. Put simply, productivity is how much we produce for each hour worked. It is the difference between digging a hole with a teaspoon and digging one with a JCB. The hole gets dug either way. The difference is that the person using the JCB has a relaxed lunch before getting on with a new hole in the afternoon.

When productivity rises, something remarkable happens. Businesses make more money. Workers can earn more. Governments collect more tax without raising tax rates. Debt becomes easier to carry. In simple terms, productivity growth is what pays for nearly everything. Which makes the timing of last year’s downgrade rather unfortunate. Just as official forecasters were becoming more pessimistic, Artificial Intelligence (AI) was arriving. Perhaps the biggest productivity opportunity since someone had the idea of putting a wheel on a barrow and, rather efficiently, inventing a new word at the same time.

Much of the now deafening noise around AI focuses on dramatic and negative headlines. Will it replace jobs? Will it kill us all? Meanwhile, millions of people have simply started using it. You use it. I use it. And we can see what it can do. If AI achieves even a fraction of the productivity gains it appears capable of, today’s worries about growth, government debt and Autumn Budgets may look very different. Not because the debt disappears, but because productivity changes the size of the economy. It grows the cake.

That is why AI is a genuinely hopeful story, not just a scare story. Businesses will have opportunities to become more efficient, more profitable and to do things that were previously uneconomic. The OBR’s economists may, of course, be right. But we are not betting against millions of people armed with the economic equivalent of a JCB.

Remember, remember the Autumn Budget? Perhaps. But some forecasts may eventually be better suited to the bonfire.