Yesterday took us another step through the Brexit looking glass.

A few months ago ministers claimed they had economic assessments about Brexit “in excruciating detail”.

Then they claimed they didn’t exist. Or if they did they were called something different. Which of course wasn’t the same thing at all.

Then we found that there was an assessment after all. And it showed that under every scenario which the Government modelled including a Free Trade Agreement with the EU the UK would be worse off than it would have been otherwise.

And to put the icing on the cake the minister in charge of Brexit turned up at the despatch box to rubbish the document – his own Government’s assessment of Brexit - and to repeat the claim that discussing these things was really not in the national interest. The government, he said, would decide what they wanted to tell us about these complicated matters sometime before a final vote on leaving.

What to make of all this?

First, on the processology the government has been anything but straight with parliament or the public about what they have been doing. Whether it’s through carelessness, a tendency to busk or something worse, the shift from claiming to have excruciating detail to having none at all then having an evolving something or other leaves it hard to trust what Ministers say on this issue.

But the main point in this case – and almost all others in politics – is not the process one. It’s about the substance. The Government’s assessment shows that Ministers are being advised that the UK could lose between two and eight per cent of future GDP growth and that this will be most keenly felt in sectors like chemicals, clothing, manufacturing, food and drink, cars and retail – sectors which collectively employ millions of people in the UK and which generate billions in tax receipts for vital public services like schools and the NHS.

That lower growth would mean a country with lower incomes and a lower standard of living than would otherwise be the case.

Ministers hide behind the excuse that releasing such information would undermine the country’s negotiating position, the inference being that those who want this information released want to act against the country’s interests.

In this world, information is under the sole ownership of ministers. Parliament and the public will be allowed to see only what Ministers decide, when they decide.

This isn’t just a political argument. It is an attempt to downgrade the role of a representative democracy. In their eyes its only purpose is to be a cheerleader for the referendum result.

The irony is not hard to see. The real undermining of the national interest here does not come from those who want to know about the economic consequences of Brexit. It comes from pursuing a policy which you know will make your country poorer than it would have been otherwise in order to satisfy nationalist ideology. It comes from putting the appeasement of factions within a political party above the leadership task of securing the greatest prosperity for the greatest number of people.

Ministers have made themselves look absurd with all their somersaults over impact assessments. They should now desist from the authoritarian claim that withholding information about these options is in the national interest. Telling the public that ignorance is bliss won’t wash in the twenty first century. The only interest served by the withholding of information about our Brexit future is the self- interest of the Tory ministers and other Brexiteers who are embarrassed by the content of the government’s own documents.

What they are reluctant to admit is that they are prepared for someone else to pay the economic price for the fulfilment of their nationalist dreams. It won’t be their job of course. Or their mortgage. Yesterday’s report shows that the regions hardest hit will be the West Midlands, the North East and Northern Ireland. Exposing the consequences is not undermining the national interest. It is the least the public can expect from the ministers charged with delivering this project, some of who have been its greatest cheerleaders.