It’s not often that M&G’s retail bond team link to education pieces; they tend to be more interested in inflation threats and sovereign defaults. But this morning, the guys at @bondvigilantes drew investors’ attention to research published in the current issue of The Spectator on the true economic cost of British educational failure. It makes more sense than you might think. Britain’s sluggish economic growth can, actually, be traced to the systematic failure of its state schools. We’re living in an era where ‘work’ is something done with the brain, rather than the hands – so a nation’s prosperity depends on how well those brains have been trained.

CoffeeHousers will be familiar with the moral scandal of the way state schools teach the richest best, and poorest worst (see the FT’s graph of doom). Every week, we see examples of this outrage. Just last week, Ofsted revealed the way that bright kids are being systematically failed by state schools who set mediocre homework and don’t push them towards the best universities. We’ve long known that we can’t afford this waste of human potential. But only now can we quantify the full economic cost.

Eric Hanushek is an academic at the Hoover Institution at Stanford University who has pioneered a way of quantifying the economic cost. By using the PISA method of scoring schools’ ability, you can see how well they teach – and then, looking at various economic factors, establish a link between school quality and GDP. Prof Hanushek was commissioned by the OECD (full study here, pdf) and I met him a few weeks ago when I was at Stanford as a media fellow with the Hoover Institution. He kindly agreed to run the numbers for Britain.

What struck him, as an American, was how Britain had fallen behind so many of its former colonies. How much richer would Britain be if its schools were as good as those of Australia, Canada, Hong Kong or Singapore?

He teamed up with Professor Ludger Woessmann from the University of Munich to produce the calculations. They worked out that catching up with Australia would add 0.4 percentage points to our economic growth rate every year — far more than has been purchased by the debt-fuelled stimulus. It works out at £3.96 trillion over the lifetime of a child born today.

A more ambitious target would be Canada, which ranks fifth in the OECD league tables. Educating British children to Canadian standards, according to Hanushek and Woessmann, would mean economic growth of an extra 0.64 per cent each year. More importantly, the average worker could be paid 17 per cent more, because the economy would be far more productive. And if Britain were to have school attainment as good as that of Hong Kong? Under the Hanushek/Woessmann tables, this would give us the fastest economic growth in the West and make the average pay packet 34 per cent larger.

Here’s the full data table, and the economic metrics.

Economic effects of boosting the UK's educational attainment

Proof – if any were needed – that Britain’s plan for economic recovery should start in the classroom. But how to do it? Cash didn’t work: Brown doubled spending-per-pupil over the Labour years and schools hurtled down the league tables. Further research has underlined the absence of any link between cash and better results. So what makes the difference?

Teachers make the difference – and way more than you may think. As Hanushek puts it: ‘A good teacher can get 1.5 years of learning growth; a bad teacher gets half a year of learning growth.’ So the difference between a good and bad teacher is one year of learning, every year. Having four consecutive years of high-quality teaching, he says, can eliminate any trace of economic disadvantage. His conclusion is that ‘Family is not destiny’ – something that sounds odd to British ears, especially when surveying the backgrounds of the Cabinet. But it’s not the British class system keeping the poor down. It’s the state education system. Prof Hanushek says that if America was to sack the least effective 10pc of teachers, and replace them with average teachers, it would shoot to the top of the league tables. It’s hard to imagine such a thing happening in Britain: it’s the sort of territory that disheartens even Michael Gove.

One final point. We have seen, so far, that the City Academy programme – started by Labour under Blair and Adonis – has achieved spectacular results. If they were repeated nationally, we would be up at Hong Kong levels. This week, Stephen Twigg proudly announced that Labour would discontinue free schools, and strangle the successful experiment at birth.

Now and again, I have heard Conservative supporters moan that Cameron & Co have made so little progress (especially on the economy) that the outcome of the next election doesn’t matter so much. If you’re rich, it won’t matter: you can afford to buy your way out. But if you’re not rich, it matters a hell of a lot. Only the Conservatives believe that school choice should be for all, not just those who can afford it. Only the Conservatives believe that tackling our failed state school system is a matter of national urgency. If you’re not rich, you have only two options to get your child into a decent school: win the lottery, or vote Conservative.

School reform is not just about social justice. As Prof Hanushek’s research indicates, it’s about the economic future of our country. The stakes really are that high.

Update: I am reminded by @Toryeducation twitter feed that Gove has made it far easier to assess and fire teachers. I am asked: what more can he do? My answer: commission a Hanushek-style study to see if the effect of good (and bad) teaching is as profound in England as in the US. The myth of all teachers being as good as each other needs exploding. It’s not only insulting to teachers, but deeply damaging to pupils. To fix a problem, you need to recognise a problem. A proper study into the impact of teacher efficacy would do just that.