Much excitement – at Westminster – over the concession made by Brexit Secretary David Davis. MPs will get a vote on the Brexit deal, he told the Commons today.

It leaves rebels and the Labour frontbench having to rethink their tactics somewhat, and shows that ministers are still – amid the chaos of the May administration – still capable of pre-emptive strikes that cause their opponents difficulties. The Tory MPs who want to stop or water down Brexit now have to find a new way through in what promises to be a fraught few days  as the committee stage of the EU Withdrawal Bill is debated on the floor of the Commons. One of the leading critics of the government on Brexit, former Attorney-General Dominic Grieve, told The Guardian today:

“I welcome the announcement today that parliament will be asked to approve any withdrawal agreement by statute but it remains the case that the bill as drafted does not reflect what the government is now promising – and the bill will therefore have to be changed to meet the government’s promise. I hope that my amendment won’t be necessary but it will remain there to be debated and if necessary voted on.”

This is only round one, it seems.

But, what does the concession by Davis really mean?

Does it give MPs a chance to kill Brexit? No, not directly. Or, rather, no and maybe. The only way for that maybe to become yes – the end of Brexit, or a plea to stay in the EU, or to suspend Article 50 (which the government said today in the Lords is impossible legally) – is if Tory rebels are prepared to bring down the government. Let me explain what I mean.

MPs will vote, presumably late next year, on the proposed deal. If they reject it the UK will still leave the EU. Only it will then be forced to leave with parliament having thrown out the only deal on offer and instead leave on a no-deal basis.  In a curious way, the government is setting it up so that Parliament votes on a binary choice between the only deal on offer and, what ultra-remainers term, “hard Brexit.” A vote against the deal by ultra-Remainers thus delivers a hard Brexit. It’s a funny old world…

Imagine that happens. The MPs who killed a deal in the Commons will then, no doubt, profess themselves horrified by the “no deal” outcome and set about stopping departure. The only way then to avoid that “hard Brexit” will be for MPs to go further and bring down the government, and to force an election or to a win a vote demanding that the government tries to halt Article 50, which would have the same effect as pro-Brexit Tory MPs, and a few Labour MPs, would not stand for it. Plus, Brexiteers in the country would be at boiling point. Obviously, as this proceeds, the Gina Miller Orchestra will be playing away merrily – with Blair, Brown, Campbell and Clegg on backing vocals. The courts will be busy next year.

Ultimately, it comes down to decision time for that small group of Tory MPs. Once you get beyond all the dancing around amendments, and talk of a “jobs first Brexit” and gimmicks, and parading around on television programmes looking earnest, the choice is stark for those Tory rebel MPs. If the anti-Brexit Tory MPs – the rebel alliance – really wants to stop Brexit, they will have to organise ruthlessly in sufficient numbers to take down a Conservative-led government, by exploiting DUP concerns on Ireland and concessions or voting with Labour to keep the UK in the Single Market. They will have to choose to split the Tory party. There really are Tory peers who want them to do all this and more, even at the risk of ushering in a Corbyn government. “Will they be brave enough?” one asked me. We’ll see soon enough.