This all started after the referendum, when David Cameron decided not to send in the A50 letter on the next working day. The EU-27 first mumbled politely that was okay, then mumbled equally politely that the letter had better be sent before a year had passed. And indeed it was signed and sent shortly before a year had passed.
There was nothing formal about that, but if you want to count deadlines then that one may be the first. Or not, IMO it depends on why you're counting.
This all started after the referendum, when David Cameron decided not to send in the A50 letter on the next working day. The EU-27 first mumbled politely that was okay, then mumbled equally politely that the letter had better be sent before a year had passed. And indeed it was signed and sent shortly before a year had passed.
There was nothing formal about that, but if you want to count deadlines then that one may be the first. Or not, IMO it depends on why you're counting.