I think you understate the full impact of what the UK government has just done:

1. Even by just presenting the Bill for discussion by Parliament, the UK has breached the "Good Faith" provisions of the Withdrawal Agreement, whereby both parties are supposed to work together to resolve outstanding issues, and failing agreement, to submit to third party arbitration..

2. If the UK can unilaterally "dis-apply" and over-ride provisions of the Withdrawal Agreement, what is to prevent them from doing the same to any Trade Agreement the EU might sign up to?

3. If the EU does accept what the UK has done and enter into a further legal arrangement with the UK, what is to prevent any EU member - e.g. Poland or Hungary - to similarly "dis-apply" any aspect of any EU Treaty it has taken a dislike to?

4. At its core, the EU is no more than a series of Treaties by which its members pool their sovereignty and make compromises for the common good. If any member or ex-member is permitted to unilaterally abrogate parts of a treaty then whole edifice falls down. Presumably that is the Brexiteer intention.

5. The UK appears to assume that in the event of a no-deal Brexit, it can rely on WTO rules to enable continued access to the Single Market, albeit with tariffs on some goods. But what if the EU were to retaliate and declare that the UK, as a rogue state, will no longer be allowed a share of quotas currently allocated to the EU and apply tariffs to all UK goods, or indeed fail to recognise UK regulatory standards as equivalent and subject all UK goods to lengthy inspections and delays?

The UK could, of course, retaliate, but with 50% of UK exports going to the EU, and only 5% of EU exports going to the UK, the impact would be an order of magnitude greater on the UK economy compared to the EU. The EU could also use the tariff income to support those sectors - e.g. farmers and auto-makers, most impacted by UK retaliation.

Once you venture into the realm of illegality, there is no knowing when and where it will stop. I have long been of the view that an acrimonious divorce will lead to an ever increasing divide and divergence between the UK and EU, and that only a full scale trade war will be sufficient to force both sides to reach an accommodation.  Basically it will take a revolution in England, probably accompanied by Scottish independence and a united Ireland, before any sort of normality ever breaks out again.

Spain may revisit the Treaty of Utrecht under which Gibraltar was ceded to the British in 1714 and Cyprus may seek to recover the British military bases on its territory. Greece will seek the return of the Elgin Marbles and any number of colonial settlements could be revisited. It comes down to power at the end of the day, and without a supportive Trump in the White House England just doesn't have that much any more.

Index of Frank's Diaries