Ministers were told to “get your acts together” in a furious outburst from the House of Commons Speaker.
Sir Lindsay Hoyle blasted Chancellor Rachel Reeves for going “around the world telling everybody” about key details in the Budget.
And Sir Lindsay let loose today, questioning whether MPs would need to bother attending the House to hear Ms Reeves deliver her first Budget on Wednesday, given “we’ll all have heard it” already.
Ms Reeves last week signalled she would rewrite the way Government debt is measured.
During a round of broadcast interviews while attending the International Monetary Fund meeting in Washington DC, Ms Reeves confirmed a technical change in the way she would measure progress against the target of managing debt.
It is expected Ms Reeves will use the Budget to open the door for the Government to spend billions more on long-term infrastructure, such as replacing dilapidated buildings on the public sector estate.
Sir Lindsay said: “Members may be wondering how they will get a seat on Wednesday.
“To be quite honest, the way it is going you won’t need to.
“It’s not acceptable, I don’t want it to continue and I want to treat this house with respect.
“It is totally unacceptable to go around the world telling everybody rather than the these members.
“They were elected by their constituents and they deserve to be treated better.
“Wasn’t it funny, when it was the previous party, the opposite side were complaining to me.
“Get your acts together all sides and treat Members with respect.”
The Chancellor is planning to announce a cut to the earnings threshold at which employers pay national insurance and an increase in the rate of contributions.
Capital gains tax, inheritance tax and fuel duty are also expected to be in her sights.
Meanwhile, the £2 cap on bus fares introduced by the Conservatives will be lifted to save cash.
Sir Lindsay, making a statement, told the Commons: “In media interviews last week the Chancellor announced that she intended to introduce changes to the fiscal rules relating to the funding of day-to-day spending through tax receipts and to the measurement of the public debt.
“These are major new policy announcements with significant and wide-ranging implications for the Government’s fiscal policy and for the public finances.
“It is evident to me that this should therefore have been made in the first instance in this House and not to the world’s media.
“This principle is clearly and unambiguously set out in paragraph 9.1 of the Ministerial Code. While this can hardly be described as a leak – the Chancellor herself gave interviews on the record and on camera – the premature disclosure of the contents of the Budget has always been regarded as a supreme discourtesy to the House.
“Indeed, I still regard it as such.
“I am very, very disappointed that the Chancellor expects the House to wait nearly a full week to hear her repeat these announcements in the Budget statement on Wednesday.”
Responding to the Commons Speaker’s criticism, the Prime Minister’s official spokesman said: “I don’t want to comment on parliamentary matters, but it’s entirely routine for government to to make announcements in the run up to budgets and spending reviews.
“But obviously we will also ensure that Parliament has all the requisite time to scrutinise measures clearly.
“The Chancellor will be in front of Parliament on Wednesday, and indeed, there will be days of Budget debate subsequently at which parliamentarians will be able to scrutinise budget measures.”
