It's hard to know where to start with the customs union position paper. It is such a mess, such a full-spectrum catastrophe of ineptitude and wishful thinking, that it's honestly quite difficult to choose which bits of it to single out for criticism.
On Sunday, Phillip Hammond and Liam Fox wrote a joint piece for the Sunday Telegraph agreeing that the UK would not stay in the customs union during transition. There is no particular reason to do this, except for the religious zeal of hard Brexiters. Staying in would allow British business to enjoy certainty and consistency as we left the EU and reduce the amount of work the UK government has to do before Brexit day. But regardless, that is not happening, so now we are full steam ahead to leave, even in the transition period.
What would this transition period entail, if not customs union membership? Well, it seems to mostly involve customs union membership. There would be a "continued close association" for a "time limited period". This – there should really be a laughter track – "could involve a new and time-limited customs union between the UK and EU Customs Union, based on a shared external tariff and without customs processes and duties between the UK and the EU". In other words: a customs union. The British plan is to leave the customs union and then create a new customs union which does exactly the same thing as the one it just left.
It is quite mad. But there is of course one reason, and one reason only, that this Alice in Wonderland nonsense is being countenanced. This imaginary new customs union would allow Britain to negotiate trade deals. Disgraced former defence secretary Liam Fox is upset that he is not legally allowed to do his new job as international trade secretary while we're in the customs union. So this is the solution. But even here the government does not appear to know what it is asking for. They admit the UK will not be able to implement any new trade deal, but are unclear about whether it would be able to sign them. Is it just going to talk to partners about them? Because if so, that is something it is already doing, as David Davis admitted this morning.