Can you hear the drums a banging?

Here's what Theresa May said on 17 January 2017.

I am equally clear that no deal for Britain is better than a bad deal for Britain.

And the likelihood of our leaving without a deal increased last week when, as the Sunday Times revealed, Government lawyers began to brief that there was no need for the UK to meet any future financial obligations to the EU.

This was doubly significant. First, because the Government's position increases the likelihood of the talks breaking down. And, second, because the fact of briefing newspapers revealed that the Government was still in the business of managing public expectations up. And why would the Government continue to lead "the British people... to expect a future that seems to be unreal and over-optimistic", as John Major put it? Unless it was preparing the ground to blame the EU when the talks fail?

Other prominent Brexiteers, too, are paving the way.

Last week David Davis warned Government Departments to prepare for that outcome.

And last night Nigel Lawson said, in essence, that he expected it.

As the Prime Minister made clear in her excellent Lancaster House speech and as the subsequent White Paper reiterated, no agreement would be better than a bad agreement. Sadly—and it is sad—a bad agreement is all that is likely to be on offer.

(It's tempting to compare these words with his "almost certainly" when he was urging a Leave vote on the country in February last year -

but that would be beside the point. Brexiters, as Walt Whitman might have observed, contain multitudes.)

So the drums are banging. The Government is - or so it seems to me - trying to prepare the ground for us just to walk out.

I do not write to address what the consequences of such a decision would be. Enough to note that the effects of doing so are profound and extend far beyond the narrowly mercantile upon which most attention has been focused. And to note that such an outcome does not reflect the will of the people: only 25% support it.

What I want to do is make one or two observations about the law.

Can Theresa May, a Prime Minister who has never been offered to the public, just walk out? What power does Parliament have, given her weak personal mandate, to restrain her?

I begin with Article 50. Relevantly it states:

3. The Treaties shall cease to apply to the State in question from the date of entry into force of the withdrawal agreement or, failing that, two years after the notification referred to in paragraph 2, unless the European Council, in agreement with the Member State concerned, unanimously decides to extend this period.

So, as a matter of EU law, we leave when a withdrawal agreement says we do or, if there is no agreement, two years from the notification.

Putting it another way, as a matter of EU law, if Theresa May just walks out, Parliament has ample time to rescue the situation - by replacing her, by requiring that she recommence negotiations, or (most likely) by withdrawing the notification and remaining in the EU. (I assume, for reasons set out here, that such a thing is possible).

And the same is true as a matter of UK law.

Our membership of the EU flows from the European Communities Act 1972 and, unless Parliament agrees to repeal it, we will as a matter of UK law remain in the EU.

The Government proposes to deal with this by asking Parliament to pre-authorise Theresa May to repeal the ECA. Here's how it puts the matter:

And this pre-authorisation, the Government intends, will come in the misnamed Great Repeal Act.

But there is no practical need for this step to be pre-authorised.

If a withdrawal agreement is struck, it will, as all sides agree, be struck within 18 months of the notification. That leaves plenty of time for the Prime Minister to seek Parliament's permission to repeal the ECA mindful of that agreement.

And if Theresa May proposes to leave without a withdrawal agreement this must be a decision for Parliament. The Conservative Party has no manifesto mandate for it. The assessment that we leave with no deal would be the personal assessment of an Prime Minister who has never been offered to the electorate and who has a very weak personal mandate for it. And it would defy the presently expressed will of the people.

Parliament should retain the reins of power. If we are to leave without a deal, Parliament must make that decision. And I think it will. Let me make a bold prediction: I do not presently think that Theresa May will succeed in persuading Parliament to pre-authorise the repeal of the European Communities Act 1972. There is no need for it - and her demand that it does simply expresses her preference for personal power over Parliamentary sovereignty.

Stand back.

As a matter of EU law we cannot leave without a deal inside two years. And as a matter of UK law we cannot leave without a deal unless Parliament says so; Parliament can stop us leaving inside two years - whatever Theresa May wishes.

The Brexiteers can bang their drums. But Parliament need not dance to their beat.

[twitter-follow screen_name='jolyonmaugham']