The Tories were today granted an emergency three-hour debate on the Chancellor's Pre-Budget Report tomorrow.
Speaker Michael Martin granted the debate after shadow chancellor George Osborne said it was an "absolute disgrace" that the Government had not come forward with one.
Mr Osborne said: "They are running away from the arguments because they are losing the argument."
Tories cheered the announcement of an emergency debate, which is rarely granted by the Speaker.
It came after the Conservatives claimed the PBR amounted to a full Budget, which is normally debated over five days and voted on.
Calling for the debate, Mr Osborne said: "It's an absolute disgrace that the Government have not conceded a debate on this.
"This wasn't just a Report but a crisis Budget and a reckless gamble with the public finances.
"It introduces a £20 billion fiscal loosening and a £40 billion package of future tax increases.
"The VAT changes, which add £12 billion to the national debt, will come into force next Monday - before any Parliamentary approval is possible and without the opportunity to raise the widespread scepticism that the public and retailers have expressed about its merits and costs."
Mr Osborne said Alistair Darling's PBR also contained the "prospect of a future rise in National Insurance, which the Institute of Fiscal Studies has just confirmed hits anyone on incomes of over £19,000 and is already damaging confidence in a future recovery.
"The news that the Government is set to borrow more than any Government in history and the national debt will double to a trillion pounds has shocked the entire country."
He went on: "If this had formally been called a Budget there would now be four whole days of debate on it. Instead this Government refuses to have even one.
"They are running away from the argument because they are losing the argument. These are the issues the entire country is talking about. We should be debating them in this chamber."
Mr Martin said: "I am satisfied that the matter raised by you is proper to be discussed under standing orders."
Dozens of Tory backbenchers, who had crowded into the chamber, stood in support of Mr Osborne's demand for an emergency debate.
Amid loud cheers and waving of Order papers, the Speaker confirmed it would be held tomorrow and last three hours.
Earlier, before the Speaker's ruling, Gordon Brown's spokesman told reporters at a regular Westminster briefing: "The Prime Minister's view is that the Government is very happy to debate the Pre-Budget Report in the House of Commons or anywhere else.
"Clearly, this is a matter for the business managers but there will be numerous opportunities during the course of the next week in the Queen's Speech debate to debate fully the Government's economic policies."
In a point of order following the ruling, Labour's Nigel Griffiths (Edinburgh S) was shouted down by roars of "Yes" from the Tory benches.
He asked: "Is it in order for honourable Members to pile into this chamber...to pile into this chamber on an important statement on employment of which they have shown no interest in in order to demand a statement tomorrow?
"Why should it be that those who have no interest in the issue of unemployment because they created so much, should have such a say in this place?"
Speaker Martin ruled: "Order! It is up to Honourable Gentlemen and Right Honourable Members when they come into the chamber.
"All I can say is there have been occasions when I have been sitting in this chamber, when there has just been a few Honourable Members, on important matters."
To Tory cheers he added: "I often wish they would pile in more often."
In a further point of order, Tory former Chancellor Kenneth Clarke (Rushcliffe) joked: "Now that you have allowed three days debate, three hours, can I ask you whether there is any procedural reason why the Leader of the House (Harriet Harman), who is in her place, should not now rise to alter the business of the House for tomorrow and the day after to allow a full debate on what has actually been the most significant Budget statement we have had in this House for the last couple of decades?
"Would you invite her to do so as we are meant to have control over taxation and public spending in this House which is what makes us the supreme legislature in the country in theory?"
Speaker Martin ruled: "You mustn't push your luck - it was three hours I was giving you, not three days."
He said there was no need for the parliamentary timetable to be changed as he had ruled the debate would take place tomorrow.