The Northern Ireland “backstop” is the fall-back position currently being negotiated as part of the UK/EU Withdrawal Agreement with regard to treatment of the UK/Ireland border should the UK exit without an agreed deal with the EU.

Is this understanding correct?

But if there is no agreed deal with the EU, then the Withdrawal Agreement is not agreed, and so surely the backstop is also not agreed? Or is this a special case?

I think I am missing some part of my understanding here...

Edit: is the answer that the backstop is to take effect in the absence of any other solution being agreed during the transition period? So the backstop is for the scenario that the Withdrawal Agreement is agreed, but that subsequently during the Transition Period, no other solution is agreed for the border.

  • 1
    Your last edit is exactly right!
    – Relaxed
    Sep 19, 2018 at 22:45
  • "Or is this a special case?" Of what? Jun 25, 2019 at 18:55

3 Answers 3


You're correct that there would be no “backstop” if there is no deal whatsoever. As you rightly put it in your edit, the backstop is for the scenario where the EU and UK agree on a withdrawal agreement but fail to find any other long-term solution for the Irish border in subsequent negotiations.

Beyond that, understanding what the whole backstop business is about requires looking in details at the mechanics of the negotiations themselves.

What the EU has been pushing from the start (and the UK was forced to agree in principle in the summer of 2017) is that an orderly Brexit would entail two separate agreements:

  • A legally binding withdrawal agreement that must be signed and agreed by all parties by March 2019. The EU wants that deal to include provisions on a payment (for what the EU regards as the UK's current commitments under the EU 7-year budget plan running from 2013 to 2020), long-term guarantees for EU citizens currently living in the UK and a solution for the Republic of Ireland-UK border. The most difficult issue presently seems to be the border question.
  • A “future relationship" agreement covering trade, access to the single market and all sorts of ancillary agreements (on things ranging from airlines operating rights to scientific research grants). That's much more complicated and very difficult to finalize within two years (let alone the mere months available now).

There have also been many discussions on some sort of “transition period” bridging the two, with many competing interpretations of what that would exactly entail.

Initially the UK was keen on tying all these issues together and the EU insisted on sequential negotiations, discussing a limited withdrawal agreement first and then moving on to the future relationship between the UK and the EU. The UK yielded in the summer of 2017 and the EU then demanded that “sufficient progress” be made on the first agreement before opening discussions on the second one.

Now, Ireland and the EU want the border issue to be dealt with in the first agreement but what arrangements could be put in place in practice also depend on the kind of relationship the UK and EU will ultimately agree on. That's where the backstop comes in: the first agreement would leave open the possibility that some other solution is found during the negotiations on the second agreement but would already include a (rather unpalatable, to the UK at least) solution if an alternative is not forthcoming.

What this achieve is to protect Ireland's interests ahead of the negotiation on the second agreement and to extend some of the leverage the EU currently has into the negotiations happening after March 2019 (“You don't like the backstop? Come up with something we like, or else…”). It would also provide a kind of fail safe mechanism on this issue if the negotiations on the second agreement falter (including as a result of an election and cabinet reshuffle).

So in December 2017, a broad outline of what the first agreement might look like was agreed and it included the “backstop”. Legally, it will only come into force if that outline is translated into an actual agreement and both parties agree to it. If there is no deal whatsoever, then the UK is not bound by this either, legally speaking.

Based on this, the EU has accepted to start discussions on the future relationship but nobody expects those to be concluded in time for Brexit. They also insist on the December 2017 principles being implemented no matter what, even as the rest of the negotiations proceed, and published a draft agreement to that effect. By contrast, some British officials (most notably David Davis when he was still Secretary of State for Exiting the European Union) suggested that everything was still open and that the UK could backtrack on its December 2017 commitments if it didn't get enough concessions from the EU on the issues the UK regards as essential.

Importantly, even if the UK actually leaves with no deal and both sides take some unilateral measures to mitigate the negative consequences, they will still need to negotiate various agreements on air transport, financial services, medicinal products, etc. and eventually some comprehensive trade agreement. And the EU already announced that its starting position in any subsequent negotiations would be based on its current goals regarding budget contributions (the “divorce bill”), citizens' rights, and the Irish border. So the backstop wouldn't automatically be off the table.

  • 1
    Good points. Link to the nearly forgotten (by now), Dec 2017 agreement: gov.uk/government/speeches/… Sep 19, 2018 at 22:01
  • 1
    @Ben Yes, Chequers is mostly about that. But the EU seems more concerned about the Withdrawal agreement (with the backstop) than anything else. It's conceivable that both parties would agree be vague or “fudge” many issues regarding the Future Relationship Agreement to paper over disagreements and stave off a no-deal Brexit.
    – Relaxed
    Sep 19, 2018 at 22:53
  • 2
    @JonathanReez That's not exactly the question (or a very fruitful way to get at the EU's position). The EU has always insisted on keeping the border open (and more than that on avoiding any sort of physical border infrastructure, even a light one like you might find in Switzerland) but also on the fact that doing that requires a comprehensive agreement as the UK would by default leave the single market upon leaving the EU and that customs check would then be unavoidable. Maybe worth posting as a separate question on the site?
    – Relaxed
    Sep 19, 2018 at 22:56
  • 1
    @Ben I don't think so.
    – Relaxed
    Sep 19, 2018 at 22:57
  • 1
    It should be noted that the Good Friday Agreement is an entirely separate treaty between the UK and Ireland alone. The EU is effectively negotiating on behalf of Ireland here. ec.europa.eu/commission/sites/beta-political/files/…
    – pjc50
    Oct 12, 2018 at 10:39

Let me actually quote from the Dec 2017 agreement the relevant point(s):

  1. The United Kingdom remains committed to protecting North-South cooperation and to its guarantee of avoiding a hard border. Any future arrangements must be compatible with these overarching requirements. The United Kingdom's intention is to achieve these objectives through the overall EU-UK relationship. Should this not be possible, the United Kingdom will propose specific solutions to address the unique circumstances of the island of Ireland. In the absence of agreed solutions, the United Kingdom will maintain full alignment with those rules of the Internal Market and the Customs Union which, now or in the future, support North-South cooperation, the allisland economy and the protection of the 1998 Agreement.

  2. In the absence of agreed solutions, as set out in the previous paragraph, the United Kingdom will ensure that no new regulatory barriers develop between Northern Ireland and the rest of the United Kingdom, unless, consistent with the 1998 Agreement, the Northern Ireland Executive and Assembly agree that distinct arrangements are appropriate for Northern Ireland. In all circumstances, the United Kingdom will continue to ensure the same unfettered access for Northern Ireland's businesses to the whole of the United Kingdom internal market.

  3. Both Parties will establish mechanisms to ensure the implementation and oversight of any specific arrangement to safeguard the integrity of the EU Internal Market and the Customs Union.

  • Regarding point 51, have these mechanisms already been made concrete? In a no-deal scenario it's hard to safeguard the integrity of the EU internal market, right?
    – JJJ
    Sep 19, 2018 at 22:15
  • @JJJ: not exactly, because Chequers' "facilitated customs arrangement" and the EU backstop proposal differ. Sep 19, 2018 at 22:26

Assuming the UK wanted to break the December 2017 agreement (see Fizz's answer) which future governments may not feel bound to, the most likely way that the backstop would take effect is by the EU demanding it.

In the even of no-deal the UK will need to do some kind of trade deal with the EU, as trading to WTO terms will be extremely damaging. The EU will likely insist on the backstop being implemented as a prerequisite to even starting a trade negotiation.

  • (+1) I was just thinking about this when the question popped up in my notifications, I actually added a paragraph about that in my answer...
    – Relaxed
    Jun 25, 2019 at 15:50

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .