The Brexit Secretary – nominally a cheerleader for Britain’s Brexit decision - said leaving the EU would  amount to a 'paradigm change' comparable with the financial slump which rocked the UK and world economies a decade ago.

He made the claim as he answered Brexit select committee questions on why no impact assessments on leaving the EU had been carried out by Whitehall.

Mr Davis likened the Brexit paradigm change to the Credit Crunch paradigm change – which turned economic models on their head and proved almost all economic forecasters wrong. 

He used that example to explain why Whitehall had not carried out Brexit impact assessments on the possible economic impact of quitting the EU.

He said: “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. The Queen famously asked why did we not know.

“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.

“You don't need to do a formal impact assessment to understand that if there is a regulatory hurdle between your producers and a market, there will be an impact.

“It will have an effect, the assessment of that effect is not as straightforward as people imagine.”

Mr Davis had previously argued against releasing the full detail of Brexit impact assessments, arguing they could damage the UK's hand in negotiations with the EU.

Meanwhile the Commons Select Committee on Exiting the EU has repeatedly demanded access to the documents on how Brexit will affect different sectors of the UK economy.

Now the minister has revealed no such documents exist, despite saying just last month the “sectoral analysis” was “contained in a range of documents”.

Speaking before the committee, Chairman Hilary Benn said: "So just to be clear, has the Government undertaken any impact assessments on the implications of leaving the EU on different sectors of the UK economy?

Mr Davis replied: “not on sectors…there’s no systematic assessment of the impact".

Asked by Hilary Benn to clarify his answer as to whether impact assessments existed, Mr Davis added: “no”.

Mr Benn added: "So the Government hasn’t undertaken any impact assessments of implications of leaving the EU for different sectors of the British economy. So there isn’t one, for example, on the Automotive sector?”

David Davis said: "No, not that I’m aware of no."

Mr Benn asked: “Is there one on aerospace?”

Mr Davis replied: “Not that I’m aware of no

Mr Benn continued: “One on financial services?"

The Brexit secretary added: “Well I think the answer is going to be no to all of them.”

Mr Davis has long made reference to the documents, telling Andrew Marr in June: "In my job I don't think out loud and I don't make guesses.

"Those two things. I try and make decisions. You make those based on the data.

"That data is being gathered. We've got 50 - nearly 60 - sectoral analyses already done"

The Brexiteer went on to tell the committee the "usefulness of such a detailed impact assessment is near zero" arguing that creating them "was not a sensible use of resources."

Mr Benn, a Labour MP, went on to confront Mr Davis with previous statements he had made about the existence of the documents

He said: "Well if you’re saying the usefulness of that is near zero, why did you tell the Foreign Affairs Committee on the 13th of September 2016, and I quote, ‘There is the sectoral analysis, we are working through about 50 cross-cutting sectors what is going to happen to them.'

"That sounds like an impact assessment to me.

"What did Lord Bridges of Headley mean, when he told the House of Lords EU internal subcommittee on the 13th of October 2016, when he said ‘we have segmented the UK economy into roughly 100 production sectors, we have looked at those to understand the size and contribution that each of these sectors makes to the economy, and used that to support our analysis of the impact on them of Brexit'.

"Now that sounds very clear to me that the Government has been looking at the impact on individual sectors and yet you told us a moment ago that you haven’t done that yet.

"Either it has happened or it hasn’t."

Mr Davis went on to defend the prior comments, arguing "Just because you use the word impact doesn’t make it an impact assessment"

The comments have evoked anger from MPs, who had long been attempting to gain access to the non-existent documents.

SNP MP Joanna Cherry Tweeted: ”So David Davis has just told the Brexit Select Committee that no impact assessments exist. 

“I repeat. UK Govt has carried out no impact assessments re economic effects of Brexit.”

Seema Malhotra, MP for Feltham and Heston, added: “David Davis has just admitted that the Government have not conducted a single economic impact assessment on the impact to Brexit to our economy. 

“Staggering. A dereliction of duty.”

Bill Esterton, MP for Sefton Central, said Mr Davis had either been dishonest or incompetent.

He wrote: “Did he know that the impact assessments didn’t exist when he said they did? 

“It was either incredibly incompetent or incredibly dishonest. 

“Either way, how is Davis still in his job?”