Where do we go from here? key questions on backstop
Q. One more time, remind me what the backstop is?
A. The backstop is a mechanism by which a hard border on the island of Ireland can be avoided after Brexit. It ties the UK to EU customs regulations "unless and until" an alternative solution is hammered out during the negotiations on a future trade agreement between the EU and UK. Initially the backstop was to apply to Northern Ireland only, but Theresa May asked for a UK-wide backstop in order to prevent the possibility of a border down the Irish Sea.
Q. So Theresa May negotiated the backstop?
A. Yes. The PM was one of the biggest champions of the backstop until recent days.
Q. She previously told MPs that there could be no Brexit deal without a backstop. Why did she tell MPs to vote for an alternative then?
A. Mrs May can't get her Withdrawal Agreement through the Commons due to the backstop. Her minority government is underpinned by the DUP which is vehemently opposed to it, as are many of her MPs.
Q. What do MPs want instead of the backstop?
A. The UK is talking about "alternative arrangements" - but it hasn't tabled any.
Q. What happens now?
A. No one knows. There is little sign Mrs May can reverse the huge defeat the treaty suffered in Parliament two weeks ago. The EU says it will not renegotiate the Withdrawal Agreement or the backstop protocol within it, but could rework the political declaration setting out post-Brexit trade terms that may offer a clearer way of avoiding the backstop - say by keeping the UK in a customs union. That, however, remains anathema to Mrs May.
Q. And if there's no deal?
A. If no one gives ground, the UK will leave the EU on March 29. Fresh talks on how to avoid a hard border would then have to start between the UK and EU - but custom posts would be firmly on the horizon.
Q. So what happens to the Republic if Mrs May demands a replacement for the backstop?
A. Its EU partners insist they will stand by it and defend the backstop. But they also want to avoid a no deal. If there was no deal, the Republic would not be able to let the only EU land border with the UK stand open for long. If it failed to check goods coming in from the UK, the Republic could find the EU raising questions over whether Irish exports to the rest of the union should remain free of all checks at their ports.