I agree. As a practical matter the apparatus of the EU government will decide in situ what dispensation, if any, to proffer members' that recant secession. That is how the EU rule-making becomes insitutional.

The UK is out numbered.

Veto prerogative of any one EU member state in no way rescinds or negates the UK's A50 action. It (dis)approves terms of settlement. It does not terminate secession.

The EC and EP have proffered the UK several options to mitigate its inevitable "third-country" status.

Tory gov has declined them all, even the future "association" compromise that Verhofstadt plants on the table once a month to lure Tory gov into any commitment to rational, negotiated process.

Make no mistake: Tory gov did NOT "conclude" any agreement to UK/IE border control in Dec '17 or March '18.

Diversity is the key to economic and political evolution.