Nick Timothy:

It would be diplomatically, constitutionally and politically wrong to let MPS take over the negotiations

On Tuesday, Dominic Grieve MP complained that “the irrationality of the debate on the detail of Brexit is truly chilling”. Critics who said his “meaningful vote” amendment was designed to block Brexit, he claimed, were causing our ability to have a rational debate to “evaporate”. But whether Mr Grieve means it or not, his “meaningful vote” amendment is effectively a “stop Brexit” amendment. And it is possible, in the spirit of rational debate and without engaging in personal abuse, to explain why this is the case.

Parliament voted for the Brexit referendum and the decision to begin the process of withdrawal: it approved triggering Article 50 by a margin of four to one. As Lord Pannick QC argues, this is now, legally speaking, irreversible: “The bullet has been fired and nothing will bring the bullet back to the gun.”

Remainers, however, have long worried about what happens when the Article 50 process ends. If EU law says Britain automatically leaves when the deadline comes, what happens if no deal has been agreed? What happens if the Government reaches a deal with the EU with which Parliament disagrees?

According to ministers, the choice Parliament will face is to leave on the terms negotiated by the Government, or leave with no deal. And they are right: the European treaties assert that the withdrawal process can last no longer than two years, and Parliament cannot approve a deal that is not on the table. Undeterred, however, Mr Grieve and his allies campaigned for a “meaningful vote” for Parliament. And in response the Government accepted that the withdrawal treaty will be voted upon by both Houses of Parliament, as early as possible.

This was not enough for the rebels and Mr Grieve defeated the Government in the Commons in December. The Withdrawal Bill now says ministers can introduce regulations implementing the withdrawal treaty only “subject to the prior enactment of a statute by Parliament approving the final terms of withdrawal”.

But then the House of Lords went further. By a large majority, it voted for Viscount Hailsham’s amendment, which would, in several prescribed circumstances, see the Commons wrest control of the negotiations from the Government.

When this week the Government tried to overturn the Hailsham amendment – by promising, if Parliament rejects the Government’s deal with the EU, that a minister would make a statement to Parliament within 28 days – Mr Grieve proposed yet another amendment. This was only defeated at the last moment when ministers promised to produce another compromise. Mr Grieve’s plan, which is very similar to Hailsham’s, could still be revived in the Lords.

Ministers and rebels might yet come to terms. But regardless, the Hailsham and Grieve amendments are unacceptable for several reasons.

The first is constitutional. It is the responsibility of the Government, not Parliament, to negotiate international treaties. The Lords and Commons – consisting of nearly 1,500 parliamentarians – cannot negotiate. Nor should they: Parliament’s responsibility is to scrutinise and approve or reject what the Government negotiates.

The second reason is diplomatic. If, in the event that there is no agreement by November and ministers need to win a showdown vote in the Commons, or if there is no agreement by February and the Government “must follow any direction approved by the Commons”, there will be no incentive for the EU to negotiate at all. The Grieve amendment will make a bad deal – or no deal – more likely. And this will be used by Remainers as an excuse to hold a second referendum, or stop Brexit altogether.

And this is the third reason: the “meaningful vote” will be used – whether Mr Grieve desires this or not – to try to stop Brexit. All the MPS who support his amendment opposed Brexit and make no secret of their unhappiness that Britain is leaving the EU. Most avoid saying they want to overturn the referendum, but Vince Cable spoke for many of them on Tuesday when he said, “stopping Brexit is one option we need to consider”.

Lord Malloch-brown, who runs the anti-brexit group Best for Britain, has said: “We must win the meaningful vote... That is likely to trigger a new referendum, or election. We must prevail decisively so reassuring Europe that our return will be permanent.” Other anti-brexit peers – who have no risk of being voted out of their ermine – are open about their intentions. Lord Bilimoria said the “meaningful vote” could “stop Brexit”. Viscount Hailsham said his amendment was necessary because without it “a decision to remain within the European Union was not an option”.

“Unchangeable decisions,” he asserted, “have no place in a democracy.” But one is unchangeable, it seems: the decision 45 years ago to join the EU. If you want to understand the “meaningful vote”, just listen to its advocates: this is not about democracy, it is about stopping Brexit.

READ MORE at telegraph.co.uk/opinion