Labour leader Ed Miliband declared his ambition to “rebuild Britain as One Nation” yesterday, as he sought to place his party firmly in the political centre ground.

While sacrifices need to be made, those with the broadest shoulders should bear the largest burdens

The One Nation slogan was first used by Conservative Prime Minister Benjamin Disraeli in the 19th century and has long been linked with the political centre-right, and Miliband made no bones about the fact that he was stealing it from the Tories.

David Cameron has lost the right to call himself a One Nation Prime Minister or claim that “we are all in this together” because of the way he has governed and his decision to hand tax cuts to millionaires while cutting services and benefits for the poor, he said.

Delivering his keynote speech without notes to Labour’s annual conference, Miliband explained how his upbringing as the child of Jewish refugees from Nazism and a comprehensive schoolboy in north London helped to form his political beliefs.

In deeply personal passages, the self-professed atheist described himself as a “person of faith”, whose faith was not in a religion but in a shared value system which involves the duty to work together to make the country better and never to shrug his shoulders at injustice.

Miliband said that Britain’s One Nation spirit was shown in the Second World War, when people of all backgrounds worked together to defeat Hitler’s Germany, and in the post-war era of Labour prime minister Clement Attlee, when they worked together to rebuild the battered country.

He stressed that he was not offering a return to the politics of Attlee or Disraeli, but calling upon the country to show the same spirit in rebuilding Britain’s economic prosperity in the wake of the financial collapse and recession.

Britain has overcome its greatest challenges by coming together as one nation in the past, and can overcome the challenges of 2012 by doing the same now, he said.

He set out his proposals for a One Nation banking system, in which deposits left by ordinary savers in high street branches cannot be used in the “casino” activities of the same bank’s trading arm; One Nation education, providing a “gold standard” vocational education with English and maths to 18 for children who are not going to university; and One Nation business, with reforms to takeover rules and shareholder rights to encourage long-term investment.

Aides said that Mr Miliband wrote the speech himself over the course of the past few weeks, and decided to deliver it without notes to achieve a more direct and authentic connection with his audience in the hall and at home watching on television.

The move will inevitably spark comparisons with Cameron’s bravura no-notes performances when he was fighting for the Tory leadership in 2005 and at his party conference in 2007.

While making only glancing reference to internal party critics or the Liberal Democrats, Miliband turned his fire directly at Cameron’s Conservatives for their record in office. People who voted for change in 2010 have found that nothing has changed and that the economy was getting worse not better, he said.

A truly One Nation government would recognise that, while sacrifices need to be made in the current difficult economic situation, those with the broadest shoulders should bear the largest burdens.

A Labour administration would show its One Nation credentials by governing for both the private and public sector and for the squeezed middle as well as those in poverty, said Mr Miliband.

And a One Nation Labour government would be different from New Labour because it would not be silent about irresponsibility at the top, but would hold the most powerful in society to account.

Mr Miliband won warm applause from delegates as he reminded them of Conservative chief whip Andrew Mitchell’s altercation with police who refused to open the Downing Street gates to let him cycle through.”

“You can’t be a One Nation Prime Minister if your chief whip insults the great police officers of our country by calling them plebs,” he said.

And he brought the audience to their feet by saying that, despite their belief that they were “born to rule” and would be good at governing, the Conservatives have turned out to be incompetent.

“Have you ever seen a more incompetent, hopeless, out-of-touch, U-turning, pledge-breaking, make-it-up-as-you-go-along, back-of-the-envelope, miserable shower than this Prime Minister and this Government?” asked Mr Miliband to loud applause.

Mr Miliband reeled off a list of the Government’s mishaps, including taxes on caravans, churches, pasties and grannies.

He ridiculed Mr Cameron’s closeness to former News International executive Rebekah Brooks and his exchange with her of text messages with the sign-off “LOL”.

The speech lasted 65 minutes, and the applause went on for three minutes as he was joined by his wife Justine.

He then left the stage with his wife to shake hands with supporters.