Sir Lindsay Hoyle has slammed Rishi Sunak's pre-Budget PR drive, telling the Chancellor that policies should be announced to MPs first because 'tradition matters'.
Much of Mr Sunak's eagerly-awaited fiscal statement has been pre-briefed by the Treasury to the press.
But Sir Lindsay, the Commons Speaker, said 'at one time the Budget was never revealed to the media' ahead of time.
He said it is 'important that people hear it on the floor of the House' first and suggested that approach is something 'we've got to get back to'.
Meanwhile, Sir Lindsay said he expected Mr Sunak to 'sit through' the entirety of post-Budget questions from MPs and that he must not 'dash off' in order to hold his pre-announced press conference at 5pm.
Sir Lindsay Hoyle today slammed Rishi Sunak's pre-briefing of Budget measures as he told the Chancellor 'tradition matters' and policies should be first set out to MPs in the House of Commons
Mr Sunak will deliver his Budget at 12.30pm today and then hold a press conference at 5pm
Numerous measures contained within the Budget, including an extension of furlough, a new mortgage guarantee scheme and extra cash for pubs and shops, were announced in the days leading up to today.
Mr Sunak will deliver the Budget in the Commons at 12.30pm and he paved the way for his address yesterday by publishing a glitzy PR video on Twitter.
But his approach has angered Sir Lindsay who told Sky News that all Government policies should be set out to MPs first rather than being pre-briefed to the media.
Speaking on the eve of the Budget, Sir Lindsay said: 'At one time the Budget was never revealed to the media.
'My worry is what will be new tomorrow and I think that is a worry that we've got to get back to.
'Tradition matters and it's important that people hear it on the floor of the House, not briefing newspapers before and certainly not dashing off afterwards to tell them how good they were.
'We will judge that ourselves by doing it live in the Commons.'
Mr Sunak has said his post-Budget press conference will be the first ever held by a UK government.
Once the Chancellor has set out his Budget in the Commons he will be grilled on its contents by MPs - a process which can take multiple hours.
Sir Lindsay has warned Mr Sunak not to try to make an early exit just so he can prepare for the press conference.
He said: 'I'm hoping he's not going too quickly, because I expect him to sit through.
'I want him to listen to what the leader of the opposition has got to say and challenge him on his budget.'