Boris Johnson has been bragging that in the event of the No Deal meltdown that he wants, Britain won't have to pay the £39 billion "divorce bill" to the EU.
The £39 billion cost is to cover Britain's debts and liabilities to the EU, for example the cost of paying pensions to British MEPs and workers to have worked in EU institutions like the European Parliament, or the European Medicines Agency.
The EU have made it absolutely clear that Britain will simply stay in limbo until the "divorce bill", the rights of EU citizens, and the Irish border issue are dealt with - so unless the UK wants to exist as an isolationist economy, the bill will have to be paid sooner or later.
However if Britain does attempt to walk away without covering these costs, it sends a very clear signal to the rest of the world that the UK is a rogue state that abandons its trade partners on a whim, and then refuses to cover their debts and liabilities.
Who is going to sign up to a trade deal with the UK when they've been given an absolutely crystal clear demonstration that the UK government will simply renege on the agreement at some point in the future if it suits their interests to do so?
But things begin to look even worse when you put this in the context of what the Tories actually want to do in the event of No Deal.
One of their 'genius plans' is to unilaterally reduce tariffs on almost all imports to 0% (because under WTO rules you can't offer favourable tariffs to one country without offering it to all countries, unless it's through a specific trade agreement).
So the UK will reduce import taxes to 0%, while all other countries will leave their tariffs on UK exports in place (because it would be unlawful for them to reciprocate, unless they do it through a specific trade deal).
This strategy is Unilateral Economic Disarmament, and it will undoubtedly cause absolute havoc with British manufacturing, agriculture, and export industries.
Imagine trying to survive when the UK market is suddenly flooded with cheap Chinese imports with 0% tariffs, while the products you're trying to sell overseas are still subject to import tariffs.
But aside from the direct impact of such a ludicrous economic suicide strategy, it's also a massive impediment to signing up to new trade deals because it burns most of our negotiating capital.
Why would other economies offer to reduce their tariffs on imports from the UK, when UK tariffs on their exports are already set to zero?
They'd obviously end up asking for something else in return, and one of the first things that comes to mind is favourable immigration rights for their citizens (which would be more than a bit of a bummer for the bigoted xenophobe demographic who voted Brexit to 'make the nasty furriners go home' wouldn't it?).
And they're certain to ask an even higher price still if the UK government goes rogue and attempts to shaft the EU27 by refusing to cover their debts and liabilities, because nobody in their right mind ever offers the most favourable terms to the most unreliable and incompetent people in the room.
£39 billion is a huge amount of money, and it's absolutely criminal that the public weren't warned that quitting the EU would come with such a high price tag when we were asked to make a decision on continued membership. But the cost of quitting without paying what's owed will obviously be even higher.
Pissing off all of your neighbouring economies by brazenly ripping them off is an absolutely terrible move, and demonstrating that you're an unreliable trade partner on the international stage is even worse, especially given that our crackpot Tory government are intent on deliberately burning away our negotiating capital by committing Unilateral Economic Disarmament at the same time.