A Treasury Minister has claimed it would have been difficult for the independent watchdog to assess the Government's controversial mini-Budget because there was "a lot of detail".
Top Tory Andrew Griffith suggested the Office for Budget Responsibility would have struggled to get through the 40-page document in time - directly contradicting the watchdog.
He was also forced to admit that Liz Truss ’s tax-slashing blitz was behind the economic turmoil of the past week.
The Prime Minister is standing firm on her plans and sought to blame the chaos on global factors such as the war in Ukraine rather than accepting criticism for spooking markets by promising £45billion in tax cuts without independent forecasts.
Ms Truss and Chancellor Kwasi Kwarteng met OBR chief Richard Hughes today for crunch talks as the Government scrambles to restore its economic credibility.
Treasury Committee chairman Mel Stride said the watchdog would likely demand a "rethink" of the plans, saying: "I suspect it will say this circle cannot be squared".
The OBR revealed yesterday that it had been ready to issue a forecast in time for the mini-Budget in a letter published by the Treasury Committee.
The financial statement on Friday could not be called a proper Budget because the Government didn't publish independent forecasts alongside of it.
Mr Griffith claimed the "detail" of the growth plan made it impossible for an independent watchdog to assess it before the Government published it.
Asked by BBC Breakfast why the OBR was not given the opportunity to make an assessment of the plan, Treasury minister Andrew Griffith said there was a "lot of detail" in the document.
He added: "This growth plan is full of detail about how this Government is going to grow the economy. 40 pages. Details of infrastructure plans that have been long held up that we are going to crack through, detail about how we are going to bring forward the new clean energy revolution.
"It is for the OBR to ultimately decide how they reflect that in their plans."
Pressed about how many pages were in a normal budget document and how quickly the OBR could turn around an analysis, Mr Griffith said: "To be honest, I am not going to answer that, I just don't know. It is quite chunky."
"There is a lot of detail", he added.
After days of trying to pass the buck, Mr Griffith was forced to admit last Friday's mini-Budget did have something to do with the financial turmoil.
“That’s absolutely part of it and no-one has said anything to the contrary” he told BBC Radio 4's Today programme.
Meanwhile, Mr Stride called for the OBR meeting to be a "reset" moment as he joined a growing number of Tories expressing concern about the plans.
“You cannot come forward with multiple billions of tax cuts in a high inflationary environment with a very tight labour market and expect that along with various supply-side changes to develop the growth that’s going to pay for those tax cuts,” he said.
“That just isn’t feasible and it is not going to work. So there needs to be a rethink and that will be a very difficult conversation.”
Labour warned the PM and the Chancellor had lost the confidence of the markets and the public.
Asked whether Liz Truss's meeting with the Office for Budget Responsibility will reassure markets, shadow business secretary Jonathan Reynolds told Sky News: "It's a bit late for that now, isn't it?"
He added: "I cannot stress how angry people should be at this Government for what is without question one of the biggest unforced errors in policy-making in this country's history."
Mr Reynolds claimed that people and businesses are looking at the "entire approach" of the Government and "saying we have no faith in these institutions".
"I will be frank," he said. "I don't think either the Prime Minister or the Chancellor will ever get that back."
