The Labour leader compared his call for an end to the “irresponsible capitalism” resulting from the political consensus since the Thatcher era with the former prime minister’s economic reforms following the 1978-79 “winter of discontent”.

He tells Steve Richards, The Independent’s chief political commentator, in a BBC Radio 4 programme broadcast at 8pm tonight: “She was a conviction politician and I think conviction really matters. I think that in the 1970s, it was a similar moment, and that is the biggest parallel. It was a similar moment in the sense that a sense of the old order was crumbling and it wasn’t 100 per cent clear what was going to replace it. And the challenge of the future, of the next few years and indeed of the election, is who can rise to the scale of challenge that the country faces and who can create a project for how this country’s going to be run that is genuinely going to make our economy work, not just for a few people but much more widely.”

Mr Miliband says that in his quest for radical change, he was inspired by his late father, Ralph Miliband, a Marxist academic. “He would have encouraged me to stand up to people, however powerful they are. The point of democracy is that it is the ultimate political tool. And I mean that in the sense that there can be no set of forces in our country that are beyond the reach of democracy,” he says.