Thread by @JolyonMaugham

We're running very short on options. And (unless the EU27 come to our aid) we're realistically down to two: revocation and No Deal.

MPs need do nothing for No Deal. It is (presently) the default. But what's the minimum needed to revoke? /1

The decision to revoke needs to be taken "in accordance with our constitutional requirements" (see paragraph 58 of Wightman curia.europa.eu/juris/document…).

But what does our constitution require? /2

There has been a lot of debate on this in the legal community and there are two schools of thought. The first is that legislation is required and the second is that Theresa May could revoke without legislation. /3

If there was no legislation in the field, we all seem to agree that the Prime Minister could revoke using what lawyers call the "royal prerogative" - the power nominally of the Queen which vests in the PM and includes the power to make (or prolong) international treaties. /4

But the question which arises is whether Parliament - by adopting the Notification Act and the Withdrawal Act - has implicitly constrained the royal prerogative. Let's look at those Acts in turn. /5

No one places much reliance on the Notification Act. It gave the Prime Minister a *discretionary* power to issue the Article 50 notice. But it didn't oblige her to do give that notice. And so can't easily be read as limiting her power to revoke it. /6 legislation.gov.uk/ukpga/2017/9/s…

It is the Withdrawal Act that is said to raise a much more serious challenge to the continuing existence of a royal prerogative power to revoke the Article 50 notice. legislation.gov.uk/ukpga/2018/16/… /7

By enacting machinery preparatory to our departure from the EU - see here for example legislation.gov.uk/ukpga/2018/16/… - the argument runs, Parliament expressed an intention that Article 50 should not be revoked. /8

A very powerful articulation of that viewpoint by @Prof_Phillipson and Alison Young can be seen here ukconstitutionallaw.org/2018/12/10/gav… /9

But there is a small school - including me - of a different view. We say that Parliament expressed its intention as to whether we should leave the EU in the Notification Act and its intention was that the PM should have a discretion. Nothing there excludes the prerogative. /10

And when it comes to Withdrawal Act, we say Parliament was proceeding from an *assumption* - given the PM's notification under the Notification Act - that we were going to leave but didn't express any view on whether we *should* leave because that had already been decided. /11

I know it sounds odd but Parliament does from time to time proceed on the basis of a predicate that sometimes turns out to have been wrong all along - or sometimes just ceases to be right. /12

What does all this mean?

Ideally, there would be legislation to remove all doubt. But what about if that doesn't happen? And now we get, I think, to the killer argument. /13

So if Parliament votes for Theresa May to revoke and she does and we think we're still in the EU and her decision to revoke is subsequently challenged in court what does a judge do?

Remember, time is very short. /14

Will a judge really say 'No, contrary to the intention of Parliament and the Prime Minister; and despite the fact everyone thinks we're inside the EU; and notwithstanding the profound implications for the country and the EU; I am going to say we are outside the EU'? /15

Not in a year of Sundays.

So if, to avoid the No Deal they have already rejected, MPs vote for a last gasp revocation and Theresa May revokes that will, imo, be good enough. /ENDS