I see that the Professor of Economic History at All Souls College, Oxford, Kevin O’Rourke, has pointed out that under the extension agreement published by the EU under “LEGAL ACTS: EUROPEAN COUNCIL DECISION taken in agreement with the United Kingdom extending the period under Article 50(3)TEU”
In item (12)
This extension excludes any re–opening of the Withdrawal Agreement. Any unilateral commitment, statement or other act by the United Kingdom should be compatible with the letter and the spirit of the Withdrawal Agreement, and must not hamper its implementation. Such an extension cannot be used to start negotiations on the future relationship.
Then Item (13)
The European Council will review progress at its meeting in June 2019.
Which could be interesting.
But the major point is that any new prospective leader has no right to re-open the Withdrawal Agreement – whatever they may say.
If they do decide unilaterally, to tear it up, that will bode very ill for any subsequent trade agreement with the EU or anybody else for that matter. Who could trust the UK? It would become as unreliable as the USA under Trump – but without being a global superpower, just a newly friendless, European offshore island.
Of course any Tory Party leader would also have to have the confidence of the house which they might not be able to achieve. Even spreadsheet Philip Hammond has so far refused to guarantee he would vote for a Tory government in a confidence motion taking Britain to a no deal exit. But they might just play for time as Parliament will be in recess for a lengthy period after any leader is likely to be elected. Labour would have to act quickly and decisively to organise a no-confidence vote and I hope they are already getting their no-confidence alliance in place now!
To do otherwise would allow a Tory administration simply to try to run down the clock.
And that way lies a WTO Brexit, when the WTO is already itself in disarray, as Trump has vetoed appointment of all new judges.
And such an outcome would of itself simply show to the world that the UK could not be relied upon to keep to its agreements.
So why would anyone even bother negotiating?