Long-range photos of people's notes as they emerge from Whitehall meetings are now a sub-genre of political journalism. You'd have thought people had seen it happen too many times to make the same mistake themselves, but clearly not. Only press offices and contacts offer a more consistent stream of information.

Yesterday's shot of the notes carried by the aide to Tory vice-chair Mark Field is more important than the usual variety, because we have so little information about the government's Brexit plan – or if indeed they have one.

Business secretary Greg Clark has said he doesn't recognise the contents and Downing Street has distanced itself from them. But this means very little. Downing Street distances itself from everything said about Brexit. They are a stone wall through which no information can be transmitted. Even when Liam Fox made a speech at the WTO about Britain's soon-to-be-independent status – something which would only be possible outside the single market – Downing Street refused to confirm that that was what it meant. A Downing Street denial means nothing.

But that alone does not mean the note is an accurate description of government policy, or even that it purports to be. It appears to be from a meeting in the Brexit department, but that does not mean it was an official briefing. Sure, it could have been David Davis himself, talking in an official capacity, but it could just as likely have been someone more junior talking in a non-official capacity. We just don't know.

What we do know is that the notes tally perfectly with what we know of the reality on the ground and the government's negotiating aims. That's troubling, because if these notes are accurate we are in very serious trouble.

The note appears to stick to the spring timetable for triggering Article 50. "Headlines won't change from now until March," it reads. A transitional deal is then raised and dismissed. "Loathe to do it," the note reads. "Whitehall will hold onto it. We need to bring an end to negotiations."

The notes outline the final arrangement. "What is the model? Have cake and eat it…. Canada Plus – more on services."

So if this note represents the aims of the government, it would suggest that they're still intent on triggering Article 50 in March, refusing any transitional arrangements, refusing to stay as a member of the single market, and then leaving in March 2019 with a 'Canada Plus' deal by March 2019. This plan will be disastrous.

As the note says, manufacturing is much easier to deal with than services. It is a relatively simple thing to organise your tariffs on eggs for instance, and to come to an agreement on what needs to be on the packaging of those eggs. It is quite another to get British citizens to accept the legal qualification of someone who trained in Romania. That's why services are much more detailed and complex additions to trade deals than goods.

This does not mean that deals on goods are easy. They will still take around five years for a decent deal. It's just they take less time to settle than services. Canada's deal, which the note envisages us using as a model, took seven years and focused almost exclusively on goods. That is not an unusual period of time. But because our deal would focus on services, it would take much longer. The note doesn't mention the fact that our deal would also involve the massive complication of politics, which was something largely avoided in the Canada case (although even there, what little politics there were almost derailed the deal in the Belgian region of Wallonia).

So the first thing you'd want if you were going for that deal is a transitional arrangement. The two years offered by Article 50 are not enough. The period between the end of Article 50 and the signing of the deal will see tariffs on our manufacturing goods, suffocating bureaucratic requirements on products being shipped to Europe, a migration of City firms to the continent so they can maintain their passporting rights, and countless other damaging economic effects. It'll hammer us. And it'll hammer the poor and middle-earners first and worst of all.

But the government still refuses to discuss an interim plan. The reason? Paranoia. As the note says: "Whitehall will hold onto it."

This suggests the government's refusal to countenance an interim deal is political, not economic. They are scared civil servants will use it to make it the new normal. Or possibly even worse, a base camp to eventually get Britain back into the EU. This is exactly what we hear from Brexiters in general. There are no answers to the tough questions of how Britain can make a stranglehold timetable more tolerable, so instead they fall back on conspiracy theories about the imaginary forces of Remainer darkness trying to control things behind the scenes.

This is where the unscientific hysteria of Brexit meets government. The dangers of the current timetable are not refuted, or even addressed. They are ignored. That document, if it does confirm the government position, is full of the same wishful thinking, fact-free discourse and emotional paranoia that has typified Brexit arguments since the referendum.

The tragedy, for those who voted Brexit and would be happy with something approaching a Canadian deal, is that this will make their desired policy catastrophic, when, with the right timetable, it needn't be. The tragedy for everyone else is that it will make us much poorer, for no reason at all except the shrill self-defeating lunacy of those in government.

We should hope that these notes don't reflect policy. But unfortunately their goals and tone are very much in keeping with the government's approach to Brexit. And that should make us very worried indeed.

Ian Dunt is the editor of Politics.co.uk. His book – Brexit: What The Hell Happens Now? – is out this week from Canbury Press.

The opinions in politics.co.uk's Comment and Analysis section are those of the author and are no reflection of the views of the website or its owners.