They called it the 'moron premium'. It was September 23, 2022, and Liz Truss's nascent government had announced £45billion of tax cuts – funded entirely by borrowing, rather than corresponding cuts to public spending.The markets went haywire. The notorious 'bond vigilantes' who trade global government debt were appalled at her fiscal irresponsibility. They dumped British bonds, known as gilts, en masse.In response, the interest rate or 'yield' on those ten-year bonds exploded: from 3.03 per cent to 4.42 per cent. This made it agonisingly more expensive for Truss and her equally inept chancellor Kwasi Kwarteng to borrow.The Treasury's bill to service public debt, along with the government's cost of doing business at all, soared.This was the moron premium in action. Truss, of course, resigned soon after her infamous 'mini budget', her 49-day tenure making her the shortest-serving prime minister in British history – famously outlasted by an iceberg lettuce.That was only four years ago. It's hardly ancient history. But Andy Burnham appears to have ignored those lessons completely.Less than a year ago, our new Prime Minister airily opined: 'We have got to get beyond this thing of being in hock to the bond market.'The only way of achieving this, of course, is for a government to live within its means and not borrow more than they can afford from those markets, but that is not the Labour way.