Which is true - there are two Vienna Conventions on dividing treaties, assets and debts but neither has been ratified by any of the major developed nations. So it's all down to negotiation.
That is the basis for London's unilateral decision that Scotland is a "successor state" with no rights or assets and not a "continuing state" which would share rights and assets with the rest of the UK (even though this is counter to the Vienna Conventions).
But Scotland is not a successor state when it suits Alistair Darling and a continuing state when it doesn't. No rights, no debt. This is not an opinion but a statement of fact confirmed by the Treasury. And despite bluff and bluster from Unionists, you can't default on a debt you never had.
If London can't persuade Scotland to accept a fair debt agreement by being reasonable, Scotland is free to walk away. We would be a state with massive natural and human resources, a great geostrategic position and no debt. It is simply not said enough - Scotland already has everything it needs to be successful and does not need anything from the rest of the UK. If London intransigence forced us to walk away we'd be more than fine.
"But you'll be crippled by high borrowing costs," say Unionists who hope no-one knows anything. Iceland actually did allow a real default of its banks at a time when its economy was a disaster. They had a bond issue oversubscribed at borrowing rates not much higher than usual.
Scotland would be in a much stronger position. We'd be a rich, debt-free country. Borrowing money would be easy. The idea that the money markets would punish Scotland in solidarity with George Osborne is silly.
Be clear: in a negotiation the side with least to lose sets the terms. All Scotland has to lose is debt. It is the rest of the UK's per capita debt that would rise 10% overnight.
So what might those terms be?
If we do not use sterling, we could subtract the cost of setting up a foreign currency reserve from any debt liability we accept. That would enable us to set up a Scottish pound as an independent currency pegged to sterling - our money will look the same, be called the same and be worth the same. But we would control it.
As our commitment to fairness for the citizens of England, Wales and Northern Ireland we could agree to a British Aid Payment, a fixed sum that we will pay each year for a set period of time to help the remainder of the UK to deal with its debt problem. It would be a fixed sum as we cannot be responsible for the borrowing costs of another nation if it mismanages its economy.
But just as London seeks conditions for a sterling agreement, we should seek conditions for a British Aid Payment. Much of the debt was the result of tax avoidance and bank bailouts which benefited the wealthy and corporations at the expense of everyone else. As a result Scotland should demand a 25% write-off of all debt to be paid for by a one-off windfall tax on individual and corporate wealth. If London does not agree this, Scotland could unilaterally subtract 25% from our British Aid Payments anyway.
We could choose not to seek any physical assets from the remainder of the UK other than those that are in our territory. We could instead subtract the cost from our aid payments and rebuild them ourselves, stimulating the Scottish economy.
The rest is detail.
Half a century since the British establishment lost its empire it remains addicted to macho posturing.
It isn't Scotland that started this fight - the Scottish Government has been excessively reasonable. But if Scotland is forced to fight, people need to know that Scotland will win.
Robin McAlpine is director of the Jimmy Reid Foundation. He is writing in a personal capacity based on his blog www.cmonscotland.org