Im not trying to be cute, as this I dont know either. But, and heres the rub, he could have issued A50 on the friday as pledged. No one had told him, definitively, he couldnt. If they had, then he had deceived us, Parliament and the EU council of his intention.
If that then was found to have been issued illegally by a subsequent judgment in UK courts, the UK would have had to notify the EU that the A50 was illegally issued and must be disregarded.
Except, that it wasnt. And we couldnt.
Under Lisbon, A50 and the decision to issue it is a matter for the constitution of the member state.
At the time of issuing, DC was acting legally. Only at the subsequent time of UK judgment, was DC then deemed to have acted illegally. The ECJ would not be concerned with any post notice domestic judgments of a member state, and certainly not any constitutional spats.
OR did DC, only receive a phone call from the sniggering judiciary, on the morning of Friday 24th? And if that was the case, did he leave a message on the fridge for the next occupant?
(not really wanting to flog this dead horse too much.....but we're all in limbo awaiting the final chapter of the Trump)