Chancellor George Osborne has rejected suggestions that the Treasury was responsible for leaking his Budget.
Many of the proposals contained in the package were predicted in the days leading up to last week's announcement.
However giving evidence to the Commons Treasury Committee on 27 March 2012, he said no minister, official or special adviser in the Treasury had released the information in advance.
He added that he was "angry" that tax changes were widely known before his official Budget statement was given in Parliament and said he would rather they had not appeared.
The committee also took evidence from the top civil servant at the Treasury, Sir Nicholas Macpherson, about how the Budget culture has changed since he began work at the department 27 years ago.
He said the process was much more secretive in the past and that people would have been "appalled" by what happens now.
However he added that he was confident that Treasury officials had not been responsible for any leaks.
The budget statement to MPs on 21 March contained a number of proposed changes to tax and allowances, including the 50p top rate of tax cut to 45p.
The personal income tax allowance will also be raised to £9,205 from April 2013, in an attempt to take a number of people out of tax - although a change in the higher tax threshold will mean that around 300,000 people will move to the higher tax band.
Mr Osborne said the Budget "rewards work" but Labour Leader Ed Miliband labelled it a "millionaire's Budget".