Brexit Secretary David Davis has admitted the Government has not carried out an overall assessment of the impact of Britain leaving the European Union.
Appearing in front of the Exiting the European Union Committee, Mr Davis made the admission after being asked by its chair Hilary Benn why no assessments had been submitted ahead of the session.
Last week, Mr Davis gave the committee 850 pages of what he terms "sectoral analyses" but no forecasts of the Brexit impact.
Mr Benn said: "Is the reason you have not handed over the assessments because you don't have them, is that correct?"
Mr Davis replied: "The sectoral analysis that were started back in 2016 are essentially looking at what the industries consist of, looking at the size of them in terms of revenue, capital, and employment and so on.
"Looking at their involvement in the European markets, looking at their regulatory structure and so on."
He added: "Now it's all very useful and it's the under-pinning of a lot of policy but it's not a forecast of the outcome of leaving the European Union or indeed various options there of."
"What we tried to do was to give you as best we could under the conditions...without undermining our negotiating position, and without compromising commercial confidentiality or market sensitive data," Mr Davis added.
Mr Benn then asked the Brexit Secretary to clarify his statement, to which he replied "there's no systematic impact assessment".
"The answer is no," Mr Benn pressed, to which Mr Davis agreed "no".
The Brexit Secretary also told MPs leaving the European bloc will lead to a "paradigm change" in the UK economy in a similar way to the 2008 financial crash.
He added that in this such circumstances any assessment of the potential impact of the change on various sectors of British industry using existing economic models would not necessarily be "informative".
"I'm not a fan of economic models because they have all proven wrong. When you have a paradigm change - as happened in 2008 with the financial crisis - all the models were wrong."
"Similarly, what we are dealing with here in every outcome - whether it is a free trade agreement, whether it is a WTO outcome or whether it is something between that on the spectrum - it is a paradigm change.
"We know not the size, but the order of magnitude of the impact," he added.
Mr Davis's admission that no sectoral impact assessments have been made by the Government provoked outrage among opposition MPs, with calls for his resignation as Brexit Secretary and for him to face investigation for contempt of Parliament.
Labour member of the Brexit committee, Seema Malhotra, described the failure to make assessments as "a dereliction of duty".
While Green Party co-leader Caroline Lucas called for the 68-year-old to resign, branding the situation "beyond farcical".
She continued: "Davis is either grossly incompetent, or someone who struggles with the truth and treats MPs with contempt. Either way, he should be out of his job."
Former Liberal Democrat leader Tim Farron also said the Tory MP for Haltemprice and Howden to stand down, calling for "Dexit: an exit from the duplicity and dither of David Davis" as he had "misled Parliament and... turned incompetence into an art form".
While the party's current leader, Sir Vince Cable, described the decision to commit the UK to leaving the customs union without a formal assessment of its impact as "gross negligence".
Scottish National Party MP Joanna Cherry said Mr Davis's evidence appeared to "directly contradict what he and other UK Government ministers have previously told Commons' committees", which she said was "pretty serious."
At least two MPs - Labour's David Lammy and the SNP's Pete Wishart - also approached Commons Speaker John Bercow to ask whether contempt proceedings could be triggered.
But the Speaker said he would await the conclusions of the committee before considering the issue.
It comes as Brexit talks with EU leaders stalled earlier this week when the prime minister pulled out of a potential deal after Northern Ireland’s Democratic Unionist Party objected to a draft Irish border proposals.
Foreign Secretary Boris Johnson has called on the EU to give an immediate green light to talks on post-Brexit trade relations, rather than insisting on waiting for a breakthrough over the Irish border.