Parliament is to be given a take-it-or leave-it vote on the final Brexit deal before the UK leaves the EU.
Brexit Secretary David Davis said the terms of the UK's exit, such as money, citizen rights and any transition must become law via a new Act of Parliament.
Labour welcomed a "climbdown" but some MPs warned of a "sham" if ministers could not be asked to renegotiate.
This was unexpected.
So, it's the 30th March 2019 and it's going down to the wire between the the EU and UK negotiators. Finally, minutes before midnight and the deal is agreed. This, by the way, is a scenario that David Davis has said may happen.
The clock strikes midnight, it's 31st March 2019, the day the UK leaves the UK! Except one "little" snag, parliament hasn't voted for the deal yet....
Analysis by Laura Kuensssberg:
I know this doesn't sound that exciting unless you are as much of a nerd as I am. However, the Brexit secretary's announcement in the House of Commons in the last few minutes really matters.
It matters because the Brexit deal that shapes the future of the country will now be the subject of a specific new Act of Parliament that MPs and Lords will have to approve in early 2019, before we leave the EU.
How they hell is this going to work? How could parliament vote on the deal line-by-line as the law will allow, if we have already left the EU? What if parliament says no, they don't like the deal, what happens then?
I am sure Tony Blair, Cleggy and Gina Miller must have had a good chuckle today.