After the chancellor admitted growth forecasts had been adjusted downwards and the nation's borrowing had increased, Miliband seized on the latest Office for Budget Responsibility figures, saying they showed "real" household incomes had fallen for three years.
In his Commons response to the budget, Miliband mocked Osborne on the day the chancellor launched his official Twitter account. "All he has to offer is just more of the same budget. Today, the chancellor joined Twitter. He could have got it all into 140 characters: growth down, borrowing up, families hit, and millionaires laughing all the way to the bank. #downgraded chancellor," he said.
Drawing on research by the House of Commons library, the opposition claimed a family with a single income of £20,000 a year would be £600 worse off by 2015 than they were in 2010, even taking account of other measures such as the rise in the income tax threshold.
"It's official: Britain is worse off under the Tories," said Miliband.
Labour sought to highlight the coalition's struggle to revive the economy and a second issue now likely to define the next general election: living standards.
After accusing the chancellor of a string of broken promises on improvements to the national debt, deficit and economic growth, Miliband said: "Who is paying the price for the chancellor's failure? Britain's families. In his first budget he predicted that living standards would rise over the parliament. But wages are flat. Prices are rising. And Britain's families are squeezed."
Labour's claim that the government's austerity programme is to blame for the sustained low growth was the other theme of Miliband's often theatrical speech, which had Labour MPs chanting along with him.
He repeated a trick from prime minister's questions by demanding that David Cameron and other cabinet members admit whether they would benefit from a cut in the top rate of income tax from 50p to 45p for people earning more than £150,000 a year, which comes into force at the start of April.
"This is the chancellor's fourth budget," he began. "Every budget, he comes to this house and things are worse, not better, for this country. And all he offers is more of the same: a more-of-the-same budget from a downgraded chancellor," said Miliband, referring to the decision by the credit rating agency Standard & Poor's to end Britain's AAA rating in February.
"Under this government the bad news just doesn't stop," said Miliband, ridiculing Cameron's promise last year that "the good news will keep coming".
Miliband also highlighted the failures of previous government attempts to revive the house-building and buying markets, including last year's pledge that the right-to-buy scheme would help 100,000 people. A year later, only 1,500 have participated in the scheme.
"That's 98,500 broken promises," he added. "For all the launches, strategies and plans, housing completions are now at the lowest level since the 1920s."
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