Tory leader David Cameron attacked the Chancellor's Budget, accusing him of "wasting money on an industrial scale".
Rising to Conservative cheers after the 48-minute statement, Mr Cameron told Mr Brown that average families were paying £1,300 more "because of your Budget decisions".
Mr Cameron said: "You have finally given us a tax cut. You normally do that before a General Election but you are in such a deep hole you have had to do it before the leadership election."
He said Mr Brown was conceding what the Tories had said "all along": "You can increase spending and you can cut taxes. Yes, you can share the proceeds of growth."
Mr Cameron then responded to noisy Labour MPs: "It is a bit like Stalin. They are cheering him on now, he'll wipe them out later."
He added: "Your great experiment in tax and spending has failed. You are an out of date politician wedded to state control. The question everyone is asking is where has the money gone?"
Mr Cameron said Mr Brown could "not run away" from his record: "You are the Chancellor who has put the tax burden up.
"You are the Chancellor who has taken one tax down but put 99 taxes up. The average family is paying £1,300 more because of your Budget decisions.
"I have to say we will check carefully what is happening to the aligning of national insurance because we think it might be hitting middle-income families."
He went on: "Let me tell you what the Chancellor's real problem is, it is not that he is a Stalinist who holds all his colleagues in contempt - although I have to say that probably doesn't help, it is that he has wasted money on an industrial scale."
