Why does Theresa May say negotiations with EU are continuing when no one in EU knows about them or expects them?

Prime Minister Theresa May Credit: PA

Here is a tale of two mysteries.

First the PM repeated on Monday that talks are going on with the EU to provide more legal and political assurances that the Ireland backstop, if implemented, will be of short and finite duration.

But try as I might, I can't find anyone on the other side of the Channel who is aware of any such talks or who expects any such talks.

Here is what one well placed source told me: "There are no ongoing contacts, no meetings foreseen with the UK."

This would imply that by the time the fabled meaningful vote actually takes place in the week beginning January 14, nothing about Theresa May's Brexit plan will have changed - and MPs will consign that plan in short order to the dustbin of history with an overwhelming vote against it.

Only the PM knows why she would prefer to endure that humiliation in four weeks rather than this week.

Wouldn't it be better to rip off the plaster today - and, as her predecessor David Cameron has told her, move swiftly to building a consensus in Parliament around another plan?

Theresa May has invited David Cameron to backseat drive on Brexit. Credit: PA

Unless that is, she is deliberately running down the clock to March 29 to increase the force of her argument that it's her deal or a chaotic no-deal Brexit.

Surely, since she insists she always puts the nation rather than her own interest first, she would not cynically be endeavouring to raise the stakes so as to increase the prospect (however remote) of eventual approval for a deal with which her own reputation is inextricably entwined?

So that's the first mystery.

The second is why the Cabinet will meet on Tuesday to step up planning for and spending on a no-deal Brexit, given that pretty much every minster (not quite all) regards a no-deal Brexit at the due date as economic self-harm on a scale the UK has never before inflicted on itself.

The point is that most ministers believe - as Amber Rudd and David Gauke have articulated - that the priority for the Cabinet should be to work day and night to prevent a no-deal Brexit, not spend money on making such a Brexit a bit less costly than it would (in their view) inevitably be.

The Cabinet it to step up planning for a no deal Brexit. Credit: PA

Here is the best manifestation of how far the UK is from having any sensible safety net against a no-deal Brexit: the Treasury has allocated £1.5 billion for spending on contingencies this year and £2 billion for next year, but ONLY £500 million has so far been spent.

So although on Tuesday the Cabinet will announce an acceleration of spending - including, I understand, on a public information plan to warn us all about what contingency planning we should all do, both in our private and business lives - it is simply too late to avoid a grave shock to the economy, our prosperity, to our ability (for a while) to procure the goods and medicines on which we depend.

Even the PM more-or-less admitted this, when she confirmed that as and when Dover is degraded into an appallingly narrow bottleneck for vital imports and exports of goods - as a result of new customs checks - trade would have to be diverted to other ports that may or may not have the appropriate capacity, and which will not under any scenario be able to handle all the jammed up traded.

Only £500 million out of £1.5 billion has been spent so far on no deal Brexit contingency planning. Credit: PA

In the longer term - according to well-placed Whitehall sources - the Port of Dover would have to be massively expanded and much of Kent concreted over, so that our most important entry port could handle the necessary new customs checks.

But can you imagine this House of Commons - which is implacably opposed to no-deal - approving the necessary legislation to nationalise Dover and its environs?

Truthfully I think that is even less likely than Mrs May saying any time soon that when she said Brexit means Brexit we all misheard her and she actually meant Brexit means no-Brexit.

We do live in strange times.

But there are some leaps of imagination I cannot make.