Now that a notification under Article 50 has been served the focus has moved to whether that notification might be revoked. It’s clear it can be revoked with the unanimous agreement of the remaining 27 member states. The real question concerns unilateral revocability: could the UK remain in the EU just because it changes its mind?

This is ultimately a question of law – a question the so-called Dublin case seeks a reference on. More news on that tomorrow for members of the Good Law Project and those who helped fund the case.

What I want to touch on here is a narrow point but one that is a matter of interest to a number of national governments – Italy, the Netherlands, Germany and elsewhere.

And the point is this, if the UK could unilaterally revoke, would that hand power to the UK in negotiations? And, in particular, would it enable the UK to extend the two year time limit in Article 50(3)?

If you read Article 50(3) in isolation you can immediately see the concern. How, those Governments might ask, could this two year limit be policed if the departing state could simply revoke at the end of the period and re-notify?

But here’s the thing. The law does not exist as some abstract concept in isolation. It operates in the real world. And if you consider how Article 50 might operate in the real world the concern evaporates.

A decision to notify (or, indeed, a decision to revoke that notification) must be a real decision made in the real world. Indeed, this is also what, it seems to me, Article 50(1) is driving at when it talks of a decision being made in accordance with its “constitutional requirements.”

And whether a decision to leave is a real decision made in accordance with the leaver’s constitutional requirements is a question which is easily answered. You look to the facts. In the UK we had a referendum. And it was clearly understood by both sides that if that referendum delivered a ‘leave’ verdict the UK would leave. That decision to leave is a real decision.

What about a decision to revoke?

Here, again, the concern expressed in Italy, the Netherlands, Germany (and no doubt elsewhere) that a revocation might be used as a ruse to extend the negotiating period does not survive real world scrutiny. A revocation would be a real revocation if it was taken in accordance with our constitutional requirements. If the United Kingdom decided that it wanted to revoke – most likely (as I have argued elsewhere) through the mechanic of a referendum on the Final Deal or on whether to Leave with no deal – then it would be plain to the remaining 27 member states that it was a real decision to revoke. And not a pretence to extend the United Kingdom’s negotiating period.

Those member states committed to the success of the European Union will, quite properly, be concerned to preserve the integrity of the Union going forward. The project is too important to be put at risk of gaming by parochial interests.

However, equally, there is no need for those member states – which will not want to see the EU weakened by the United Kingdom’s departure – to erect an unhelpful and on analysis unnecessary barrier to the genuinely expressed and real desire of the people of the United Kingdom to Remain.

Here we are.

I’m proud to be with you. And I’m proud to have walked with you. And I’m proud to stand with you. And I’m proud to talk to you.

Because when we work together, when we share our wealth, we all prosper. When we live as a community, all our lives are better. When we stand together we are all protected.

Sixty years ago today our community was created. Sixteen years later we joined it.

And it isn’t perfect. Francis does spend all the parish funds on his allotment. Jean Claude is very bossy. And they do come stay a lot.

But we’re not perfect either. We’re always wanting special rules, just for us. And it bugs our neighbours. But we rub along. And we prosper.

Together we are stronger. We make our garden grow.

Next week, we’ll tell everyone we’re leaving. We’re going to live on our own. All the faults are theirs. We’ll do better by ourselves. That nice Mr Trump, he’ll look after us.

But we haven’t left yet.

Next week will also see the next step in our case to establish that Article 50 is just the beginning of a journey. We have new additions to a very powerful legal team. We will file our written case. We will seek a hearing date in June. Ireland has said it wants to discuss the way forward.

The Claimants – me along with three very brave politicians from the Green Party who came forward when no one else would – are bringing this action to give the people of this country a choice. A choice they must have. A democratic choice. To remain if they want to remain.

I can’t tell you what answer the courts will give. But what I believe is that pushing the Article 50 button is like starting a journey. If we want to turn around, we can turn around.

Will we turn around? No one knows. No one knows what the future holds.

We voted to leave in a very different world. No President who thought NATO obsolete. No one threatening to tear up trade rules. And we did not know what Brexit meant for the country. And we still don’t know now.

I’m not in the crystal ball business. I don’t know what the future holds. I don’t know what will happen. But I will say this: no one else does either. Anyone who tells you they know the popular mood will remain the same is lying to you. Because they do not know. Because they cannot know. Because the only certainty you can rely on is change itself.

But I’ll tell you this.

What will make Brexit happens is if you give up. If you give up now. Now, at their last moment of control. The last moment before real life walks in on their fantasy.

And takes their cake away.

It’s the hope that kills you, they say. They say that but they’re wrong. The hope will save you. It will save you. And there is hope. There is real hope. Don’t give up.

Fight for your country. Fight for our children. Fight for our future.

Thank you.

Postscript: you can watch a recording of the speech here https://youtu.be/Q4ehBWt-bpY

How, after Article 50 is triggered, will the law shape and constrain our future inside and outside the EU?

To answer that question let me make some assumptions.

First, assume that Theresa May triggers Article 50 on 29 March 2017. And, second, assume that we can unilaterally revoke Article 50. (The Dublin case is progressing. Slowly but well. The Good Law Project will publish an update next week here. Please sign up to our mailing list).

What happens next? Is there a legal path to Remaining? How will this shape and be shaped by the politics?

There are three main scenarios going forward. They involve a delicate and complex interplay of EU and UK law. I’ll set them out and then – once I’ve run through the analysis – address what seem to me to be the main points of interest.

(1) We conclude an agreement with the EU which Parliament approves. We then leave the EU on the date – it may be less or it may be more than two years from 29 March 2017 – set out in that agreement. The precise date of our departure depends on what the agreement provides: Article 50(3) says that the Treaties cease to apply to us “from the date of entry into force of the withdrawal agreement.”

(2) We don’t conclude a deal with the EU. The key fact to bear in mind is this: as a matter of EU law we remain in the EU until 29 March 2019 and we then we leave. But as a matter of UK law, whether we leave before 29 March 2019 depends upon the status of the European Communities Act 1972 (the “ECA”).

Theresa May will ask Parliament (in her so-called Great Repeal Bill) to give her power to repeal the ECA at a moment of her choosing. If you assume Parliament has not given her that power then it would be for Parliament to choose – in response to talks with the EU breaking down – whether to repeal the ECA or to take some other action. It is difficult (for me) to imagine that Parliament might ask the PM to recommence negotiations. But it could very well put back to the electorate the choice whether to leave the EU without a deal or to Remain. And if a Referendum produced a Remain result before 29 March 2019 we would Remain in the EU as a matter of both UK and EU law.

If, on the other hand, Parliament had given her that power then you would expect Theresa May to repeal the Act when talks with the EU break down. That would have the consequence that we would be out of the EU as a matter of UK law. But, until 29 March 2019, we would still be in the EU as a matter of EU law. Parliament could still in theory – I will return to consider the practice below – call a referendum on whether to leave the EU or to Remain. And if that Referendum produced a Remain result before 29 March 2019 Parliament could re-enact the ECA and we would Remain in the EU as a matter of both UK and EU law.

(A small aside. I don’t understand why Parliament should prospectively repeal the ECA. To do so is unnecessarily to abrogate a power that properly belongs to Parliament. But perhaps in the final analysis it doesn’t matter hugely).

(3) We conclude a deal with the EU and Parliament doesn’t approve that deal. This scenario may be less likely than (1) or (2) but its effects are substantially identical to scenario (2). (It is possible that our membership of the EU would, as a matter of EU law, expire on the date prescribed by the rejected agreement (see Article 50(3)). But I think the better view is that the withdrawal agreement would never “enter into force”.) So, until 29 March 2019, Parliament could choose to Remain.

So a few points emerge from this analysis and generally.

(i) Parliament still has a lot of power. Whatever the Prime Minister does, Parliament can still decide to Remain in the EU.

(ii) opinions differ but my own view is that party politics is not the insuperable barrier to Remaining that many think. This is not the place for a lengthy analysis of the point but I proceed from the premise that Labour MPs are basically Remain and there is a substantial body of Conservative MPs who are basically pragmatic. This, of course, is not to deny that the political situation could be better for those like me who still think the country’s interests are better served by us Remaining.

(iii) if you believe that leaving the EU is a bad thing, and that the public will come to appreciate this, then scenario (2) is rather striking. If negotiations with the EU deteriorate and break down we will see how the economy reacts. And we will also see the – hitherto under-examined – other non-financial consequences: for Scotland, for Northern Ireland, for the right of UK citizens living in the EU and EU citizens living here to reside and access healthcare, for air transportation and the NHS and so on. And we will see how the public reacts to this. Scenario (2) could very well confront the electorate with a stark choice between the having and the eating of cake. And at a point in time when Parliament can still react to the electorate’s choice.

This is a reality which could shape both the EU’s and our own conduct of negotiations.

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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.

Downing Street is running hard with the line that for Parliament to have a ‘meaningful vote’ on the final deal would hurt the UK’s bargaining position. See (amongst other places) here and here.

But is this true?

Let’s just clear away some undergrowth so we can focus on the question.

Let’s assume that leaving without a deal would be hugely damaging.  It would be harmful in trade terms, it would be harmful in broader regulatory terms and it would harmful for UK citizens living in the other member States who would, for example, lose the right to free healthcare.

Leaving without a deal is, then, not really an option.

What ‘having a meaningful vote’ then means (in effect) is Parliament having the ability to reject whatever deal Number 10 strikes with Brussels without us having to leave without a deal. It has that ability if it can revoke – or ask the electorate whether it wants to revoke – the Article 50 notification so that we remain in the EU.

And let’s just assume this is possible.

So what’s Number 10’s position on having a meaningful vote?

But is this right?

No, or so it seems to me at least. For four overlapping reasons.

First, it assumes that the other 27 are desperate to keep us.

If you were to ask them today, the 27 other member states would probably say they’d rather we remained. Probably – I’m not aware of any evidence. But it defies reality to assert that they are so desperate for us to Remain that they would deliberately set out to offer us an ugly deal even where the consequence of doing so might well be that we left the EU with no deal at all, hurting their citizens and businesses and ours too.

It’s even more bold to think that in two years time, after two years of exposure to our ‘have your cake and eat it’ negotiating strategy, and after two years of exposure to our rather vigorous tabloids, the other 27 remain so desperate for our continued membership that they take this risk.

This feels to me like exceptionalism on steroids.

Second, it assumes that it is better for us to Leave whatever the consequence.

We do not know what the future holds.

The vote to Leave occurred in a very different, and much more stable, world than we now live in. It was before the election of Trump who in a few short weeks has undermined NATO, undermined the WTO, threatened to renegotiate the trade deal of any state running a trade surplus with the US, threatened a border tax to discriminate against imports, threatened war against Iran and China and so on.

And – although supporters of Brexit are still running hard with the’having our cake and eating it’ line – the fact remains that we do not know what Brexit will look like. We do not know what the final deal will be. And we do not know what the consequences are.

No one making a decision of this magnitude in a climate this uncertain rationally chooses to make that decision earlier than she could. Even if she believes she is set on the right course she retains her optionality to the very last moment.

And by seeking to deny Parliament a meaningful vote what, in effect, Theresa May is choosing is irrationality. Forget the evidence, she is saying, we will leave whatever changes around us.

Third, it’s an unexplored assumption that a meaningful vote weakens our position.

The situation (without Parliament having a meaningful vote) is that we have to strike a deal within two years or suffer the consequences of leaving without one. If you want an analogy, you might compare this with having made a decision to emigrate and having booked your flight and needing to sell your car before you go. The would be purchaser wants the car but because you are up against the clock – and he knows it – your ability to hold out for the best price is limited.

That’s not a great bargaining position.

The alternative – having a meaningful vote – would give us the opportunity to decide ‘this deal is not good enough’ (or to use my analogy cancel our decision to emigrate). In that situation we are not held hostage against the clock in the same way. But, of course, there is a price attached to improving our bargaining position – we have to be prepared not to leave.

And, if you want to leave, that’s not a great bargaining position either.

You can weigh and spin these alternatives endlessly. But ultimately it seems to me that there is an air of unreality to the contention that Parliament having a meaningful vote weakens our position. We have decided to leave: the Government’s position is that the Article 50 notification won’t be revoked. And the EU knows we have decided to leave. A good deal is in our mutual interests – but there is no certainty we will be able to achieve one. No deal is in our mutual disinterest – but there is no certainty we will be able to avoid one.

And in the circumstances you get on with it and do the best you can and leave the weighing and spinning for the birds.

Fourth. Actually? This isn’t a fight about our bargaining position.

And this is the killer point.

Parliament is supreme. It can decide that it wants to remain. And even if Theresa May wants it not to be so it would still be so. It doesn’t need an amendment to the Article 50 Bill to confirm it is so. It is a fundamental tenet of our constitution.

And the EU knows this. So if the opportunity for Parliament to have a meaningful vote weakens our bargaining position then that weakening doesn’t follow from an amendment to the Article 50 Bill. It is hard-wired into our constitution. And it can’t be changed.

And all this talk from her spokesperson about “giving strength to other parties” is a mere smokescreen for that basic, undeniable truth.

So what’s all this really about?

It’s about control. Who gets to control these profoundly important decisions about whether we crash out without a deal? Or about whether we might look at the sum total of the evidence and choose to Remain? Does Theresa May, who has never been offered to the electorate as a Prime Minister, get to make them? Or does Parliament, whose MPs have a roving mandate from the electorate, get to make them?

And all the rest is smoke and mirrors.