The controversial backstop is seen by the hard-line Brexiteers as a trap by the EU to keep Northern Ireland permanently in a customs union without an option to get out if the UK wanted. In a no deal scenario, both the Irish PM and the EU presidents have said there would still be no hard border between Ireland and Northern Ireland.

So why do they insist on having it in the withdrawal agreement?

  • The Irish backstop makes little sense to me either. Even if you take the opposite view that a no-deal Brexit would make a hard border more likely, that just makes the backstop demand seem even more illogical, because if the UK will not accept it and crashes out, then it increases the chances of the outcome it is intended to prevent.
    – Time4Tea
    Commented Apr 4, 2019 at 17:05
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    The UK and the EU agreed to the idea of backstop, which basically is a legal guarantee of the verbal agreement you mentioned of not putting back an hard border. The problem is that for political reasons the DUP opposes the idea. So the backstop is controversial for internal political reason of the UK government (see Brexit: what is the UK's backstop proposal?). A legal agreement is better than a verbal agreement, because an actual law has a real power that a verbal agreement lacks.
    – gabriele
    Commented Apr 4, 2019 at 17:38
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    I'm not so sure the intent is bad as you assume. It took a long time to get peace in Ireland.
    – Karlomanio
    Commented Apr 4, 2019 at 17:39
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    @gabriele it's not only the DUP...The Hard brexiteers oppose it too simply because they believe it's a template for a permanent customs union and that even though the intention is to avoid a hard border, this can be solved by alternative arrangements. Thing is in a no deal scenario, the UK has said it wont return to hard, same as EU&NI even though that should be the proper thing to do. So, if in a no deal scenario, the border can still be invisible or at least there will be a genuine attempt at making it invisible from both sides, why must it be there?
    – Toby
    Commented Apr 4, 2019 at 17:51
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    I think, as @gabriele said, the EU and Ireland want a legal guarantee of no hard border, not just a verbal agreement and good intentions. However, many on the UK side see it as a possible legal trap. As I said, given the level of opposition to it in the UK, it seems to merely be increasing the risk of what the EU/Ireland (supposedly) want to avoid.
    – Time4Tea
    Commented Apr 4, 2019 at 17:54

3 Answers 3


For the EU, keeping a border open even if it should be closed from a strictly legal and commercial point of view will impose costs. These might include the import of non-certified products into the internal market, illegal immigration, and more. So they would rather keep the border open under conditions which permit it, i.e. with a "somewhat hard" border between Northern Ireland and the rest of the UK.

I understand why the latter option would be unacceptable from an Ulster Unionist viewpoint, but from an EU viewpoint it solves lots of problems -- the border between the Republic of Ireland and Northern Ireland is open, but the land on the other side of the open border follows common market regulations.

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    See also: Brexit: Good Friday Agreement 'hard to protect' in a no deal, which is based on an interview with Varadkar, where the latter puts forward that livestock controls would likely need to occur at the border itself. Contrary to the premise behind the question, it is not at all clear that the border would stay open on the EU side. Commented Apr 4, 2019 at 18:27
  • This is an excellent answer.... I dont know if it would be open either but it is stated by both the UK PM and Irish PM that they wont build a hard border in the event of a no deal. Infact Varadkar said it again today alongside Merkel
    – Toby
    Commented Apr 4, 2019 at 18:32
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    Illegal migration is not a big issue for the EU outside of Ireland as there are immigration controls between them. It's also not such a big issue inside the common travel area as Irish and UK citizens are free to live anywhere in the UK and Ireland, there is visa cooperation between the UK and Ireland and UK/EU citizens are likely to have visa-free visits to the EU/UK anyway. For these reasons it shouldn't be a much bigger issue than it is now. Conversely, VAT may be a substantial issue where it currently isn't (as well as non-certified products and tariff evasion). Commented Apr 4, 2019 at 20:38
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    Illegal migration is not an issue at all, not in the slightest. UK citizens have freedom of movement in Ireland regardless of EU treaties. And you cannot use Ireland as a way to get into the EU visa-free for as long as it remains outside the Schengen area. Commented Apr 4, 2019 at 21:43
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    @o.m. the Calais jungle existed because illegal immigrants want to enter the UK from the Schengen area, not the other way around. The Irish border is about a lot of things, but immigration is not one of them. Commented Apr 5, 2019 at 5:47

O.m. is correct, but in a more prosaic representation, relative to no-deal, the backstop pushes the single-market border from the interior of Ireland to the Irish Sea. This is not entirely correct, because the whole UK would be in a more limited customs union with the EU as well. So there's basically a "double pushback" that spreads out the pain of dealing with the customs checks (some get pushed to the Irish Sea, some get pushed even further to the whole UK). With no-deal, all those checks have to be performed somewhere in Ireland (even if not right at the border), where they incur a higher cost for EU, mostly in terms of risks for stirring violence or at least more nationalism in Ireland etc.

Of course the EU needs to hang some carrot for the UK to buy this (as the UK would incur a cost) or at least a stick (worse economic outcome for no-deal). So some of the rest of the Agreement does the carrot part, but it's besides the point of your question, which is limited to EU's motivation for the backstop.

As for "hellbent" that has more to do with EU showing solidarity with Ireland, negotiating tactics, a German sensitivity to borders and Troubles etc.

Germany’s foreign minister, Heiko Maas, was speaking as Ireland’s deputy prime minister, Simon Coveney, said MPs who were planning to vote against Theresa May’s deal needed to stop their “wishful thinking” that the EU would reopen Brexit negotiations.

“Some people call us stubborn, but the truth is avoiding a hard border in Ireland is a fundamental concern for the EU, a union that more than anything else serves one purpose – to build and maintain peace in Europe,” said Maas. [...]

“During the Brexit negotiations, all 27 member states agreed on a common position and stood by it. This unity includes full solidarity with Ireland. We insisted, and still do: a hard border dividing the Irish island is unacceptable." [...] said Maas in a speech to Irish ambassadors in Dublin on Tuesday.

Basically the backstop guarantees a softer border in Ireland compared to no-deal.

Not everyone in Europe was happy with this, Poland in particular raised the idea of a "5-year limited backstop" back in January; Czaputowicz, their foreign minister said:

“Obviously, that would be less beneficial for Ireland than an indefinite backstop, but much better than a no deal Brexit which is unavoidably coming our way”.

According to what Czaputowicz underlined during his comments, the EU has become hostage to Ireland’s government position in the negotiations. “The Irish also gave a pretext to treat the British harshly. Arguably, they thought the UK would at some point agree to an indefinite backstop,” but this did not happen. “Now we have a game of chicken with two cars heading towards each other,” added Czaputowicz, who said this will inevitably mean a process that will lead to a hard border.

but they went back in line quickly after they were disavowed by Germany, Ireland (of course) and the by Brussels. Which as we now now has a contingency plan for the border that isn't that hard, but still riskier (for the EU) than the backstop would be.

The dominant idea in the EU, as expressed by the Irish foreign minister:

“I made it very clear that putting a time limit on an insurance mechanism, which is what the backstop is, effectively means that it’s not a backstop at all. I don’t think that reflects EU thinking in relation to the withdrawal agreement.”

I guess that you look at it from the German perspective, in which the backstop equals peace (at least declaratively), "peace for 5 years" sounds silly. Of course "peace forever or war now" is also not a great slogan. But this is probably where the game of chicken comes in play; the more drastic terminology you use to frame the problem, the more likely it is for the no-deal to seem out of the question.

And this is actually not too far from the actual game of chicken, in which a strategy is


One tactic in the game is for one party to signal their intentions convincingly before the game begins. For example, if one party were to ostentatiously disable their steering wheel just before the match, the other party would be compelled to swerve. This shows that, in some circumstances, reducing one's own options can be a good strategy.

  • succintly put..I get the play now....If I were the UK I must insist on a time limit backstop....EU has to concede that otherwise it may be better to be in a perpetual No deal scenario and let things shape out from there. It's ridiculous the EU seems to just want to bully the UK
    – Toby
    Commented Apr 4, 2019 at 22:34
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    @Toby: That is correct only if you assume the UK has nothing to gain from the backstop. But that's not certain. Just like in the (theoretical) game of chicken, both sides (UK and Ireland+EU) may lose something if the Troubles come back. The losses might not be same for both sides though. Commented Apr 4, 2019 at 22:46
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    @Toby how is insisting on the right of the UK to renege on agreements and cause problems for Ireland not "bullying Ireland"?
    – pjc50
    Commented Apr 5, 2019 at 12:30
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    (a vital piece of the puzzle is that Ireland only formally acnowledged the existence of the UK-Ireland border in its current place in 1999. en.wikipedia.org/wiki/… )
    – pjc50
    Commented Apr 5, 2019 at 12:33
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    The backstop including the entire UK is entirely at the UK's request. The UK seem to have forgotten that the purpose of the backstop is to prevent trouble in northern Ireland, part of its own territory. It's crazy to present this as a stick that needs some carrot to compensate for it. The backstop is entirely in the UK's interest, except something is so wrong with their democratic representation that they cannot seem to see that.
    – hkBst
    Commented Apr 7, 2019 at 7:28

The UK is leaving the EU, so the EU considers the UK responsible for resolving the issues with the Irish border.

Since a hard border is not an acceptable option, other solutions must be found to solve issues like how the EU can maintain a customs frontier. The EU is concerned that the UK could simply walk away and not provide a solution, enjoying the benefits of "backdoor" access to the EU single market and forcing the EU to fix the problem itself.

The integrity of the single market is extremely important to the EU. The market is over 6 times larger than the UK market, and naturally the EU wants to protect it. Not only from illegal imports from the UK, but from complaints to the WTO that the EU is giving unfair preferential access to the UK by failing to maintain a border.

In sort the EU requires the UK to deal with problems of its own making, instead of trying to pass them off to the EU.

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    @DenisdeBernardy May's main concerns are her legacy and xenophobia. Her legacy depends on not breaking the Tory party, not setting them up to lose the next election, delivering her brexit deal, and not allowing the UK to break up. Xenophobia requires here to stick to her red line of ending freedom of movement. Nothing else matters to her, all her actions are driven by those two things.
    – user
    Commented Apr 5, 2019 at 10:19
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    @Toby no-deal with wreck the UK economy. Tories would be wiped out at the next election and Scotland would vote for independence, breaking up the UK. Northern Ireland would probably have a border poll and re-join Ireland too. Despite all the bluster she was never going to accept no-deal.
    – user
    Commented Apr 5, 2019 at 11:15
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    @user I think you mean the xenophobia of sections of the Tory party. My impression is that May thought the only way she could avoid a rebellion was a deal with the red line of ending freedom of movement. Now that she's had that rebellion anyway, she's gone to Labour to get something that passes, and the ERG are furious that they no longer have the stranglehold on policy.
    – Caleth
    Commented Apr 5, 2019 at 12:02
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    @Toby "customs union" is effectively a substitute for reunited Ireland, as it preserves the ability for goods to move across the border. No Deal will wreck the economy, the UK's own briefing papers state as such. It's only the intransigent hardliners who believe that no deal is an acceptable outcome.
    – pjc50
    Commented Apr 5, 2019 at 12:38
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    @RedGrittyBrick why would they think that? The EU didn't vote to leave
    – Caleth
    Commented Apr 5, 2019 at 14:22

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