Is Brexit Day a moveable feast?
Following my note of Tuesday that ministers are increasingly concerned time is running perilously short for the UK to conclude talks that would allow Brexit on the scheduled date of 29 March 2019, I asked a senior member of the government intimately involved in Brexit preparations whether they were planning to postpone Brexit day.
"That's not what we expect," he said.
Which is not the strongest denial I've ever been given.
But this person-close-to-May conceded that the execution of a timely Brexit will depend both on the PM hitting her target of publishing the UK's aspirations for its future relationship with the EU in the week of 9 July - AND the rest of the EU not being too hostile to the contents of the white paper that contains those aspirations.
Because, as Channel 4's Gary Gibbon pointed out on Wednesday, after the white paper is available there will ONLY be a month and a half of proper negotiating time to settle the heads of agreement for our future relationship with the EU - and finalise a workable solution to keep the Northern Ireland border with the Republic open.
So, for all but the most religiously ardent of Brexiters, Brexit day is looking like a movable feast.
Contrary to what she thought she wanted, Theresa May does have the power to delay this feast - thanks to what she saw initially saw as the hostile parliamentary pressure of rebel Tory backbenchers led by Dominic Grieve and the Labour party.
To delay the moment of exiting the EU, under the terms of the glistening new EU Withdrawal Act, requires no more than for ministers to lay a statutory instrument and a vote of MPs, which is no biggie.
Of course, the rest of the EU would also have to agree to a later Brexit moment.
Also May would have to be confident a third of her cabinet wouldn't resign at the very thought - and that would be a biggie.