"Ed speaks human", his supporters used to say, and today Ed Milband proved that he can. Speaking without notes for more than an hour, this was the best and most relaxed speech he has delivered since becoming Labour leader. The jokes were funny, the message was hopeful, and the attack lines were lethal. Returning repeatedly to the theme of "one nation", he suggested that while David Cameron had failed to live up to this tradition, he could. His "faith" (the other leitmotif) was, he said, not a religious one, but one that the religious would recognise all the same. It was defined by the belief that "we have a duty to leave the world a better place".

From there, he argued that the Tories, both heartless and hopeless, were set to leave Britain a worse place. The government's biggest mistakes - the NHS reorganisation ("you can't trust the Tories with the NHS"), the abolition of the 50p tax rate, the devotion to austerity - were all ruthlessly recalled. As, inevitably, was Andrew Mitchell's run-in with the police. But while the Lib Dems sought to make light of the incident ("my fellow plebs," Danny Alexander quipped), Miliband angrily brandished it as evidence of why the Tories could never be a "one nation" government.

Fears that the speech would be jargonistic and wonkish were dispatched ("predistribution" was nowhere to be found) as the Labour leader expressed himself in clear, accessible terms. "If the medicine's not working," he said of the economy, "you need to change the medicine. And you need to change the doctor too." And he vowed that while Labour would be forced to take tough decisions in office, he would never cut taxes for the richest, while raising them for the poorest - "those with the broadest shoulders will always bear the greatest burden." He could not wish for a more potent dividing line with Cameron's party.

But while Miliband was clearer than ever about his differences with the Tories, he also extended an olive branch to their supporters. In one of the most effective passages, he declared that he understood why they voted Conservative and why they "turned away from the last Labour government". But now that the country was back in recession and borrowing more than last year, Cameron no longer deserved the benefit of the doubt. With an eye to the right, Miliband also acknowledged that a Labour government would have to cut spending - "we've got to live within our means" - and declared that, while he would do everything possible to help the unemployed, those who could work had a "responsibility" to do so. As for the Lib Dems, Miliband, more in sorrow than in anger, lamented that the party behind the 1909 People's Budget had supported the "millionaire's budget" of 2012.

While light on policy, the speech successfully outlined a vision of a fairer, more generous society. The banks would "serve the country", rather than the country serving the banks, the "free market" in the NHS would end, and the "two nations" - the rich and the rest - would be brought together. Displaying his new-found confidence, Miliband recalled his "predators and producers" refrain, adding that "one year on, people know what I was talking about".

After this speech, the Tories will no longer be able to console themselves with the thought that while Labour rides high, Miliband is unelectable. Once seen as a drag on his party, the Labour leader will now be recognised as an asset.