Labour leader Ed Miliband tore into the Budget today after George Osborne announced plans to cut the top rate of income tax.
He told MPs: "After today's Budget, millions will be paying more while millionaires pay less."
The Chancellor used his Budget to announce that the 50p top rate of tax will drop to 45p from April next year.
In his response to the statement, Mr Miliband told the Commons it marked the end of the Government's claim that "we are all in it together".
The Chancellor announced the cut to the 50% rate, but also closed a number of loopholes and reliefs which he claimed would raise five times more from the wealthy.
He also increased the threshold at which everyone starts paying tax to £9,205, claiming millions of working people would be £220 a year better off as a result.
In a raucous Commons, Mr Miliband labelled it a "millionaires' budget" and said: "The Chancellor spoke for an hour but one of his phrases was missing.
"There was one thing he didn't say: today marks the end of 'we are all in it together'."
Mr Miliband said: "A year ago the Chancellor said in his Budget speech, 'Now would not be the right time to remove the 50p tax rate when we are asking others in our society on much lower incomes to make sacrifices.'
"That is exactly what he has done: tax credits cut, child benefit taken away, fuel duty rising - and what has he chosen to make his priorities?
"For Britain's millionaires, a massive income tax cut each and every year."
The Labour leader said the "fairness test" for the Budget was whether the Government used "every penny" to help middle income families that are squeezed.
"He has failed that test," said Mr Miliband.
Mr Miliband told Mr Osborne that voters would wonder which planet he and Prime Minister David Cameron are on.
The Labour leader also challenged Cabinet ministers to raise their hands if they would personally benefit from cutting the 50p tax rate.
Quoting back one of the Government's favourite mantras to promote transparency, he urged them: "Sunlight is the best disinfectant.
"Just nod if you're going to benefit from it, or shake your head if you're not.
"Come on, we've got plenty of time."
He said the Chancellor's "driving ambitions" for the Budget were "to deliver a tax cut for people earning over £150,000".
Mr Miliband added: "How can the priority for our country be an income tax cut for the richest 1% at a time when the squeezed middle are facing rising petrol prices, higher energy bills and tax credits and child benefit being cut?
"Think of what you could have done with the money."
Mr Miliband said Mr Osborne's growth plan had failed, adding: "Unemployment is rising month upon month upon month.
"You promised us last year the deficit would be gone by the end of the Parliament, but today you admit you're borrowing over £150 billion more than you said you would."
The Labour leader warned Mr Osborne: "Every time in the future you try to justify an unfair decision by saying 'Times are tough', we will remind you that you are a man who chose to spend hundreds of millions of pounds on those who need it least."
He blasted the Government for "wrong choices, wrong priorities, wrong values", claiming it was "out of touch", and adding: "Same old Tories."
Mr Miliband turned his fire on Deputy Prime Minister and Liberal Democrat leader Nick Clegg, whom he branded "the hapless accomplice".
Mr Miliband added: "Only the Lib Dems could be dumb enough to think George Osborne's Budget is a Robin Hood Budget - Calamity Clegg strikes again."
Referring to the Liberal Party's celebrated former leader and prime minister David Lloyd George, Mr Miliband said the party had gone from "following Lloyd George to following George Osborne".
He added: "All the Chancellor is doing for ordinary families is giving with one hand and taking far more away with the other.
"It's a millionaires' budget that squeezes the middle."
The Labour leader said calculations showed anyone earning £5 million would be £240,000 better off, branding it "the Government's very own bankers' bonus".
He added: "It's one rule for them and another for everyone else."
Returning to the decision to cut the 50p rate, Mr Miliband poked fun at the Prime Minister's recent difficulties over the revelation he rode a horse on loan to former News International chief executive Rebekah Brooks.
The Labour leader told Mr Cameron: "Now you're going to be able to buy your own horse."
Andrew Tyrie, the Tory chairman of the Treasury Select Committee, said the cross-party group would examine whether Mr Osborne's Budget did what was claimed.
He also expressed concern about the number of policies in the statement that had been leaked to the press.
He said: "I have to tell the Chancellor that several colleagues on both sides of the House have complained to me about the leaks and the briefings in the days prior to this Budget.
"All I will say at this point on that is that the Treasury Committee will be looking at it."
The committee will scrutinise Mr Osborne's claim that the Budget was a "tax reforming" one.
"We will examine whether the main tax measures live up to what it's claimed they will achieve," he said.
Dame Joan Ruddock (Lab, Lewisham Deptford) said: "I hope that when the committee does its review it will consider the fact that for an ordinary family with two children, the losses coming in this April amount to £530 and the compensation the Chancellor boasts of giving today amounts to only £220."
Mr Tyrie said: "We will take evidence on that point and on all the main measures and we will be publishing it as quickly as we can."
The main accountancy bodies would be asked to scrutinise the tax measures, he said.
They would examine the cap on tax reliefs, the yield on the 45p rate and the general anti-avoidance measure "about which a number of us have concerns", he added.
The accountants will also examine Mr Miliband's point that this was a "Budget for millionaires at the expense of the squeezed middle".
But Mr Tyrie added: "These are very uncertain times and confidence is at a premium.
"Whatever one's views about the overall Budget judgment, most people agree that confidence is bolstered when governments do what they said they will do.
"In this Budget, I think the Chancellor has done just that."
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Full text of the Budget speech